Merge pull request 'String和stdio支持' (#2) from archzero_dev into main

Reviewed-on: http://127.0.0.1/ZeroOSProject/BetterSTL/pulls/2

CMakeLists.txt

@@ -1,7 +1,56 @@
 cmake_minimum_required(VERSION 3.10.0)
 project(BetterSTL VERSION 0.1.0 LANGUAGES C CXX)
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
-add_library(BetterSTL src/BigInteger.cpp
+# 定义源文件
-    src/BigDecimal.cpp)
+set(BETTERSTL_SOURCES
+        src/big_integer.cpp
+        src/big_decimal.cpp
+        src/string.cpp)
+
+# 生成静态库 (.a 文件)
+add_library(BetterSTL_static STATIC ${BETTERSTL_SOURCES})
+target_include_directories(BetterSTL_static PUBLIC include)
+set_target_properties(BetterSTL_static PROPERTIES 
+    OUTPUT_NAME BetterSTL
+    PREFIX lib)
+
+# 生成动态库 (.so 文件)
+add_library(BetterSTL_shared SHARED ${BETTERSTL_SOURCES})
+target_include_directories(BetterSTL_shared PUBLIC include)
+set_target_properties(BetterSTL_shared PROPERTIES 
+    OUTPUT_NAME BetterSTL
+    PREFIX lib)
+
+# 默认链接到静态库
+add_library(BetterSTL ALIAS BetterSTL_static)
+
+enable_testing()
+
+add_executable(BigIntegerTests tests/big_integer_test.cpp)
+target_include_directories(BigIntegerTests PRIVATE include)
+target_link_libraries(BigIntegerTests PRIVATE BetterSTL_static)
+add_test(NAME BigIntegerTests COMMAND BigIntegerTests)
+
+add_executable(BigDecimalTests tests/big_decimal_test.cpp)
+target_include_directories(BigDecimalTests PRIVATE include)
+target_link_libraries(BigDecimalTests PRIVATE BetterSTL_static)
+add_test(NAME BigDecimalTests COMMAND BigDecimalTests)
+
+add_executable(StringTests tests/StringTest.cpp)
+target_include_directories(StringTests PRIVATE include)
+target_link_libraries(StringTests PRIVATE BetterSTL_static)
+add_test(NAME StringTests COMMAND StringTests)
+
+add_executable(IOTests tests/IOTest.cpp)
+target_include_directories(IOTests PRIVATE include)
+target_link_libraries(IOTests PRIVATE BetterSTL_static)
+add_test(NAME IOTests COMMAND IOTests)
+
+# 生成导出信息用于外部使用
+install(TARGETS BetterSTL_static BetterSTL_shared
+        LIBRARY DESTINATION lib
+        ARCHIVE DESTINATION lib
+        RUNTIME DESTINATION bin)
+install(DIRECTORY include/ DESTINATION include)
 
-include_directories(include)

IO_SUPPORT.md

@@ -0,0 +1,91 @@
+# BetterSTL cin/cout 支持
+
+现在三个核心类都支持标准输入输出：
+
+## BigInteger - 高精度整数
+
+```cpp
+#include <bstl/big_integer.hpp>
+#include <iostream>
+
+bstl::BigInteger bi;
+std::cout << "Enter a large integer: ";
+std::cin >> bi;
+std::cout << "You entered: " << bi << std::endl;
+```
+
+支持任意精度的整数输入输出，不受 `long long` 限制。
+
+## BigDecimal - 高精度浮点数
+
+```cpp
+#include <bstl/big_decimal.hpp>
+#include <iostream>
+
+bstl::BigDecimal bd;
+std::cout << "Enter a decimal number: ";
+std::cin >> bd;
+std::cout << "You entered: " << bd << std::endl;
+```
+
+支持任意精度的浮点数输入输出，精度不丢失。
+
+## String - 增强字符串
+
+```cpp
+#include <bstl/string.hpp>
+#include <iostream>
+
+bstl::String str;
+std::cout << "Enter a word: ";
+std::cin >> str;
+std::cout << "You entered: " << str << std::endl;
+
+// 可以使用 Python 风格的方法
+std::cout << "Uppercase: " << str.upper() << std::endl;
+std::cout << "Split: ";
+auto parts = str.split("_");
+```
+
+## 使用示例
+
+编译和运行演示程序：
+
+```bash
+cd /home/archzero/C++/BetterSTL
+cmake -S . -B out/build -G Ninja
+cmake --build out/build
+
+# 运行库测试
+ctest --test-dir out/build
+
+# 运行演示（需要在终端交互）
+./out/build/IOTests
+```
+
+## 实现细节
+
+### operator<<（输出）
+- BigInteger: 通过 `toString()` 输出
+- BigDecimal: 通过 `toString()` 输出
+- String: 通过 `str()` 输出
+
+### operator>>（输入）
+- BigInteger: 读取字符串，创建新对象
+- BigDecimal: 读取字符串，创建新对象
+- String: 读取字符串，创建新对象
+
+所有运算符都定义在 `bstl` 命名空间中。
+
+## 编译链接
+
+在编译你的程序时：
+
+```bash
+g++ your_program.cpp -I/path/to/include -L/path/to/lib -lBetterSTL -o your_program
+```
+
+或者使用静态库：
+```bash
+g++ your_program.cpp -I/path/to/include /path/to/libBetterSTL.a -o your_program
+```

examples/IODemo.cpp

@@ -0,0 +1,41 @@
+#include <bstl/big_integer.hpp>
+#include <bstl/big_decimal.hpp>
+#include <bstl/string.hpp>
+
+#include <iostream>
+
+int main() {
+    using bstl::BigInteger;
+    using bstl::BigDecimal;
+    using bstl::String;
+
+    std::cout << "=== BetterSTL cin/cout Demo ===\n\n";
+
+    // BigInteger 示例
+    std::cout << "BigInteger Example:\n";
+    std::cout << "Enter a large integer: ";
+    BigInteger bi;
+    std::cin >> bi;
+    std::cout << "You entered: " << bi << "\n";
+    std::cout << "Doubled: " << (bi * BigInteger(2)) << "\n\n";
+
+    // BigDecimal 示例
+    std::cout << "BigDecimal Example:\n";
+    std::cout << "Enter a decimal number: ";
+    BigDecimal bd;
+    std::cin >> bd;
+    std::cout << "You entered: " << bd << "\n";
+    std::cout << "Doubled: " << (bd * BigDecimal(2)) << "\n\n";
+
+    // String 示例
+    std::cout << "String Example:\n";
+    std::cout << "Enter a word: ";
+    String str;
+    std::cin >> str;
+    std::cout << "You entered: " << str << "\n";
+    std::cout << "Uppercase: " << str.upper() << "\n";
+    std::cout << "Lowercase: " << str.lower() << "\n\n";
+
+    std::cout << "Demo completed!\n";
+    return 0;
+}

include/bstl.hpp

@@ -1,6 +0,0 @@
-#ifndef BETTERSTL_BSTL_HPP
-#define BETTERSTL_BSTL_HPP
-
-#include <bstlint.hpp>
-
-#endif //BETTERSTL_BSTL_HPP

include/bstl/big_decimal.hpp

@@ -0,0 +1,79 @@
+#ifndef BETTERSTL_BIG_DECIMAL_H
+#define BETTERSTL_BIG_DECIMAL_H
+
+#include <string>
+#include <iostream>
+#include <bstl/big_integer.hpp>
+
+namespace bstl {
+    class BigDecimal {
+public:
+    BigDecimal();
+    BigDecimal(int value);
+    BigDecimal(long long value);
+    BigDecimal(double value);
+    explicit BigDecimal(const std::string& value);
+    explicit BigDecimal(const char* value);
+    BigDecimal(const BigInteger& unscaledValue, int scale);
+    BigDecimal(const BigDecimal& other) = default;
+    BigDecimal& operator=(const BigDecimal& other) = default;
+
+    bool isZero() const;
+    int sign() const;
+    int getScale() const;
+    BigInteger getUnscaledValue() const;
+    std::string toString() const;
+
+    // Comparison operators
+    bool operator==(const BigDecimal& other) const;
+    bool operator!=(const BigDecimal& other) const;
+    bool operator<(const BigDecimal& other) const;
+    bool operator>(const BigDecimal& other) const;
+    bool operator<=(const BigDecimal& other) const;
+    bool operator>=(const BigDecimal& other) const;
+
+    bool operator==(int value) const;
+    bool operator!=(int value) const;
+    bool operator<(int value) const;
+    bool operator>(int value) const;
+    bool operator<=(int value) const;
+    bool operator>=(int value) const;
+
+    bool operator==(double value) const;
+    bool operator!=(double value) const;
+    bool operator<(double value) const;
+    bool operator>(double value) const;
+    bool operator<=(double value) const;
+    bool operator>=(double value) const;
+
+    // Arithmetic operators
+    BigDecimal operator+() const;
+    BigDecimal operator-() const;
+    BigDecimal& operator+=(const BigDecimal& other);
+    BigDecimal& operator-=(const BigDecimal& other);
+    BigDecimal& operator*=(const BigDecimal& other);
+    BigDecimal& operator/=(const BigDecimal& other);
+
+    BigDecimal operator+(const BigDecimal& other) const;
+    BigDecimal operator-(const BigDecimal& other) const;
+    BigDecimal operator*(const BigDecimal& other) const;
+    BigDecimal operator/(const BigDecimal& other) const;
+
+    BigDecimal abs() const;
+    BigDecimal round(int scale) const;
+
+private:
+    BigInteger unscaledValue_;  // 去掉小数点后的值
+    int scale_;                 // 小数点后的位数
+
+    static void alignScale(BigInteger& lhs, int& lhsScale,
+                          BigInteger& rhs, int& rhsScale);
+};
+
+// 流运算符重载
+std::ostream& operator<<(std::ostream& os, const BigDecimal& bd);
+std::istream& operator>>(std::istream& is, BigDecimal& bd);
+
+} // namespace bstl
+
+#endif //BETTERSTL_BIG_DECIMAL_H

include/bstl/big_integer.hpp

@@ -0,0 +1,75 @@
+#ifndef BETTERSTL_BIG_INTEGER_HPP
+#define BETTERSTL_BIG_INTEGER_HPP
+
+#include <string>
+#include <iostream>
+
+namespace bstl {
+
+class BigInteger {
+public:
+    BigInteger();
+    BigInteger(int value);
+    BigInteger(long long value);
+    BigInteger(unsigned long long value);
+    explicit BigInteger(const std::string& value);
+    explicit BigInteger(const char* value);
+    BigInteger(const BigInteger& other) = default;
+    BigInteger& operator=(const BigInteger& other) = default;
+
+    bool isZero() const;
+    int sign() const;
+    std::string toString() const;
+
+    bool operator==(const BigInteger& other) const;
+    bool operator!=(const BigInteger& other) const;
+    bool operator<(const BigInteger& other) const;
+    bool operator>(const BigInteger& other) const;
+    bool operator<=(const BigInteger& other) const;
+    bool operator>=(const BigInteger& other) const;
+
+    bool operator==(int value) const;
+    bool operator!=(int value) const;
+    bool operator<(int value) const;
+    bool operator>(int value) const;
+    bool operator<=(int value) const;
+    bool operator>=(int value) const;
+
+    bool operator==(long long value) const;
+    bool operator!=(long long value) const;
+    bool operator<(long long value) const;
+    bool operator>(long long value) const;
+    bool operator<=(long long value) const;
+    bool operator>=(long long value) const;
+
+    BigInteger operator+() const;
+    BigInteger operator-() const;
+    BigInteger& operator+=(const BigInteger& other);
+    BigInteger& operator-=(const BigInteger& other);
+    BigInteger& operator*=(const BigInteger& other);
+    BigInteger& operator/=(const BigInteger& other);
+
+    BigInteger operator+(const BigInteger& other) const;
+    BigInteger operator-(const BigInteger& other) const;
+    BigInteger operator*(const BigInteger& other) const;
+    BigInteger operator/(const BigInteger& other) const;
+
+private:
+    std::string digits_;  // 无符号数字，从高位到低位
+    int sign_;            // -1, 0, 1
+
+    static std::string trimLeadingZeros(const std::string& value);
+    static int compareAbs(const std::string& a, const std::string& b);
+    static std::string addAbs(const std::string& a, const std::string& b);
+    static std::string subAbs(const std::string& a, const std::string& b);
+    static std::string mulAbs(const std::string& a, const std::string& b);
+    static std::string divAbs(const std::string& a, const std::string& b);
+};
+
+// 流运算符重载
+std::ostream& operator<<(std::ostream& os, const BigInteger& bi);
+std::istream& operator>>(std::istream& is, BigInteger& bi);
+
+} // namespace bstl
+
+#endif //BETTERSTL_BIG_INTEGER_HPP

include/bstl/big_number.hpp

@@ -0,0 +1,7 @@
+#ifndef BETTERSTL_BIG_NUMBERS_HPP
+#define BETTERSTL_BIG_NUMBERS_HPP
+
+#include <bstl/big_integer.hpp>
+#include <bstl/big_decimal.hpp>
+
+#endif // BETTERSTL_BIG_NUMBERS_HPP

include/bstl/bstl.hpp

@@ -0,0 +1,8 @@
+#ifndef BETTERSTL_BSTL_HPP
+
+#include<bstl/big_decimal.hpp>
+#include<bstl/big_integer.hpp>
+#include <bstl/bstlint.hpp>
+
+#define BETTERSTL_BSTL_HPP
+#endif //BETTERSTL_BSTL_HPP

include/bstl/bstlint.hpp

@@ -2,7 +2,6 @@
 #define BETTERSTL_BSTLINT_HPP
 
 #include <cstdint>
-#include <>
 
 typedef std::int8_t i8;
 typedef std::int16_t i16;

include/bstl/string.hpp

@@ -0,0 +1,97 @@
+#pragma once
+
+#include <string>
+#include <vector>
+#include <algorithm>
+#include <cctype>
+#include <iostream>
+
+namespace bstl {
+
+class String {
+public:
+    String();
+    String(const std::string& str);
+    String(const char* str);
+    String(const String& other) = default;
+    String& operator=(const String& other) = default;
+
+    // 获取标准字符串
+    std::string str() const;
+    const char* c_str() const;
+    size_t length() const;
+    size_t size() const;
+    bool empty() const;
+
+    // 获取/修改字符
+    char at(size_t pos) const;
+    char operator[](size_t pos) const;
+    char& operator[](size_t pos);
+
+    // 分割 - 按分隔符分割字符串
+    std::vector<String> split(const String& delimiter = " ") const;
+
+    // 连接 - 用分隔符连接多个字符串
+    static String join(const std::vector<String>& parts, const String& delimiter = "");
+
+    // 替换 - 替换第一个/所有匹配项
+    String replace(const String& oldStr, const String& newStr, int count = -1) const;
+
+    // 大小写转换
+    String upper() const;
+    String lower() const;
+    String capitalize() const;  // 首字母大写
+    String title() const;       // 每个单词首字母大写
+
+    // 判断函数
+    bool startswith(const String& prefix) const;
+    bool endswith(const String& suffix) const;
+    bool contains(const String& substring) const;
+    bool isdigit() const;
+    bool isalpha() const;
+    bool isalnum() const;
+    bool isspace() const;
+    bool isupper() const;
+    bool islower() const;
+
+    // 查找和计数
+    int find(const String& substring, size_t start = 0) const;
+    int rfind(const String& substring) const;  // 从后往前查找
+    int count(const String& substring) const;
+
+    // 去除空格和其他字符
+    String strip() const;           // 去除前后空格
+    String lstrip() const;          // 去除前导空格
+    String rstrip() const;          // 去除尾部空格
+    String strip(const String& chars) const;  // 去除指定字符
+
+    // 对齐和填充
+    String ljust(size_t width, char fillchar = ' ') const;
+    String rjust(size_t width, char fillchar = ' ') const;
+    String center(size_t width, char fillchar = ' ') const;
+
+    // 字符串转换
+    int toInt() const;
+    long long toLongLong() const;
+    double toDouble() const;
+
+    // 运算符重载
+    String operator+(const String& other) const;
+    String operator+(const char* str) const;
+    String& operator+=(const String& other);
+    bool operator==(const String& other) const;
+    bool operator!=(const String& other) const;
+    bool operator<(const String& other) const;
+    bool operator>(const String& other) const;
+    bool operator<=(const String& other) const;
+    bool operator>=(const String& other) const;
+
+private:
+    std::string data_;
+};
+
+// 流运算符重载
+std::ostream& operator<<(std::ostream& os, const String& str);
+std::istream& operator>>(std::istream& is, String& str);
+
+} // namespace bstl

src/big_decimal.cpp

@@ -0,0 +1,352 @@
+#include <bstl/big_decimal.hpp>
+
+#include <stdexcept>
+#include <sstream>
+#include <cmath>
+
+namespace bstl {
+
+BigDecimal::BigDecimal() : unscaledValue_(0), scale_(0) {}
+
+BigDecimal::BigDecimal(int value) : unscaledValue_(value), scale_(0) {}
+
+BigDecimal::BigDecimal(long long value) : unscaledValue_(value), scale_(0) {}
+
+BigDecimal::BigDecimal(double value) : scale_(0) {
+    if (value == 0.0) {
+        unscaledValue_ = 0;
+        scale_ = 0;
+        return;
+    }
+
+    // 将浮点数转换为字符串，然后解析
+    std::ostringstream oss;
+    oss.precision(15);
+    oss << value;
+    *this = BigDecimal(oss.str());
+}
+
+BigDecimal::BigDecimal(const std::string& value) : unscaledValue_(0), scale_(0) {
+    if (value.empty()) {
+        return;
+    }
+
+    std::string text = value;
+
+    // 去掉前后空格
+    size_t start = 0, end = text.size();
+    while (start < end && text[start] == ' ') start++;
+    while (end > start && text[end - 1] == ' ') end--;
+    text = text.substr(start, end - start);
+
+    if (text.empty()) {
+        return;
+    }
+
+    // 查找小数点位置
+    size_t dotPos = text.find('.');
+    if (dotPos != std::string::npos) {
+        scale_ = text.size() - dotPos - 1;
+        std::string digits = text.substr(0, dotPos) + text.substr(dotPos + 1);
+        unscaledValue_ = BigInteger(digits);
+    } else {
+        scale_ = 0;
+        unscaledValue_ = BigInteger(text);
+    }
+}
+
+BigDecimal::BigDecimal(const char* value)
+    : BigDecimal(value == nullptr ? std::string("0") : std::string(value)) {}
+
+BigDecimal::BigDecimal(const BigInteger& unscaledValue, int scale)
+    : unscaledValue_(unscaledValue), scale_(scale) {
+    if (scale < 0) {
+        throw std::invalid_argument("scale cannot be negative");
+    }
+}
+
+bool BigDecimal::isZero() const {
+    return unscaledValue_.isZero();
+}
+
+int BigDecimal::sign() const {
+    return unscaledValue_.sign();
+}
+
+int BigDecimal::getScale() const {
+    return scale_;
+}
+
+BigInteger BigDecimal::getUnscaledValue() const {
+    return unscaledValue_;
+}
+
+std::string BigDecimal::toString() const {
+    if (isZero()) {
+        return "0";
+    }
+
+    std::string digitStr = unscaledValue_.toString();
+
+    // 处理符号
+    bool negative = false;
+    if (digitStr[0] == '-') {
+        negative = true;
+        digitStr = digitStr.substr(1);
+    }
+
+    // 插入小数点
+    if (scale_ == 0) {
+        return (negative ? "-" : "") + digitStr;
+    }
+
+    if (static_cast<int>(digitStr.size()) <= scale_) {
+        // 需要前置 "0."
+        std::string result = "0.";
+        for (int i = 0; i < scale_ - static_cast<int>(digitStr.size()); i++) {
+            result += "0";
+        }
+        result += digitStr;
+        return (negative ? "-" : "") + result;
+    }
+
+    int dotPos = digitStr.size() - scale_;
+    std::string result = digitStr.substr(0, dotPos) + "." + digitStr.substr(dotPos);
+    return (negative ? "-" : "") + result;
+}
+
+void BigDecimal::alignScale(BigInteger& lhs, int& lhsScale,
+                            BigInteger& rhs, int& rhsScale) {
+    if (lhsScale < rhsScale) {
+        // 左边需要扩大
+        for (int i = 0; i < rhsScale - lhsScale; i++) {
+            lhs = lhs * BigInteger(10);
+        }
+        lhsScale = rhsScale;
+    } else if (lhsScale > rhsScale) {
+        // 右边需要扩大
+        for (int i = 0; i < lhsScale - rhsScale; i++) {
+            rhs = rhs * BigInteger(10);
+        }
+        rhsScale = lhsScale;
+    }
+}
+
+bool BigDecimal::operator==(const BigDecimal& other) const {
+    if (isZero() && other.isZero()) return true;
+    BigInteger lhs = unscaledValue_;
+    BigInteger rhs = other.unscaledValue_;
+    int lhsScale = scale_;
+    int rhsScale = other.scale_;
+    alignScale(lhs, lhsScale, rhs, rhsScale);
+    return lhs == rhs;
+}
+
+bool BigDecimal::operator!=(const BigDecimal& other) const {
+    return !(*this == other);
+}
+
+bool BigDecimal::operator<(const BigDecimal& other) const {
+    if (unscaledValue_.sign() != other.unscaledValue_.sign()) {
+        return unscaledValue_.sign() < other.unscaledValue_.sign();
+    }
+
+    BigInteger lhs = unscaledValue_;
+    BigInteger rhs = other.unscaledValue_;
+    int lhsScale = scale_;
+    int rhsScale = other.scale_;
+    alignScale(lhs, lhsScale, rhs, rhsScale);
+
+    if (unscaledValue_.sign() >= 0) {
+        return lhs < rhs;
+    } else {
+        return lhs > rhs;
+    }
+}
+
+bool BigDecimal::operator>(const BigDecimal& other) const {
+    return other < *this;
+}
+
+bool BigDecimal::operator<=(const BigDecimal& other) const {
+    return *this < other || *this == other;
+}
+
+bool BigDecimal::operator>=(const BigDecimal& other) const {
+    return other <= *this;
+}
+
+bool BigDecimal::operator==(int value) const {
+    return *this == BigDecimal(value);
+}
+
+bool BigDecimal::operator!=(int value) const {
+    return !(*this == value);
+}
+
+bool BigDecimal::operator<(int value) const {
+    return *this < BigDecimal(value);
+}
+
+bool BigDecimal::operator>(int value) const {
+    return *this > BigDecimal(value);
+}
+
+bool BigDecimal::operator<=(int value) const {
+    return *this <= BigDecimal(value);
+}
+
+bool BigDecimal::operator>=(int value) const {
+    return *this >= BigDecimal(value);
+}
+
+bool BigDecimal::operator==(double value) const {
+    return *this == BigDecimal(value);
+}
+
+bool BigDecimal::operator!=(double value) const {
+    return !(*this == value);
+}
+
+bool BigDecimal::operator<(double value) const {
+    return *this < BigDecimal(value);
+}
+
+bool BigDecimal::operator>(double value) const {
+    return *this > BigDecimal(value);
+}
+
+bool BigDecimal::operator<=(double value) const {
+    return *this <= BigDecimal(value);
+}
+
+bool BigDecimal::operator>=(double value) const {
+    return *this >= BigDecimal(value);
+}
+
+BigDecimal BigDecimal::operator+() const {
+    return *this;
+}
+
+BigDecimal BigDecimal::operator-() const {
+    if (isZero()) {
+        return BigDecimal(0);
+    }
+    return BigDecimal(-unscaledValue_, scale_);
+}
+
+BigDecimal& BigDecimal::operator+=(const BigDecimal& other) {
+    *this = *this + other;
+    return *this;
+}
+
+BigDecimal& BigDecimal::operator-=(const BigDecimal& other) {
+    *this = *this - other;
+    return *this;
+}
+
+BigDecimal& BigDecimal::operator*=(const BigDecimal& other) {
+    *this = *this * other;
+    return *this;
+}
+
+BigDecimal& BigDecimal::operator/=(const BigDecimal& other) {
+    *this = *this / other;
+    return *this;
+}
+
+BigDecimal BigDecimal::operator+(const BigDecimal& other) const {
+    if (isZero()) return other;
+    if (other.isZero()) return *this;
+
+    BigInteger lhs = unscaledValue_;
+    BigInteger rhs = other.unscaledValue_;
+    int lhsScale = scale_;
+    int rhsScale = other.scale_;
+    alignScale(lhs, lhsScale, rhs, rhsScale);
+
+    return BigDecimal(lhs + rhs, lhsScale);
+}
+
+BigDecimal BigDecimal::operator-(const BigDecimal& other) const {
+    return *this + (-other);
+}
+
+BigDecimal BigDecimal::operator*(const BigDecimal& other) const {
+    if (isZero() || other.isZero()) {
+        return BigDecimal(0);
+    }
+
+    BigInteger result = unscaledValue_ * other.unscaledValue_;
+    int resultScale = scale_ + other.scale_;
+
+    return BigDecimal(result, resultScale);
+}
+
+BigDecimal BigDecimal::operator/(const BigDecimal& other) const {
+    if (other.isZero()) {
+        throw std::invalid_argument("division by zero");
+    }
+
+    if (isZero()) {
+        return BigDecimal(0);
+    }
+
+    // 先对齐 scale，然后做整数除法
+    BigInteger lhs = unscaledValue_;
+    BigInteger rhs = other.unscaledValue_;
+    int lhsScale = scale_;
+    int rhsScale = other.scale_;
+
+    // 使用更高的精度进行除法
+    // 乘以 10^precision 来获得更多的精度
+    int precision = 10;
+    for (int i = 0; i < precision; i++) {
+        lhs = lhs * BigInteger(10);
+    }
+
+    BigInteger quotient = lhs / rhs;
+    int resultScale = lhsScale - rhsScale + precision;
+
+    return BigDecimal(quotient, resultScale);
+}
+
+BigDecimal BigDecimal::abs() const {
+    if (unscaledValue_.sign() >= 0) {
+        return *this;
+    }
+    return BigDecimal(-unscaledValue_, scale_);
+}
+
+BigDecimal BigDecimal::round(int scale) const {
+    if (scale < 0) {
+        throw std::invalid_argument("scale cannot be negative");
+    }
+
+    if (scale >= scale_) {
+        return *this;
+    }
+
+    // 简单实现：直接截断到指定小数位数
+    int diff = scale_ - scale;
+    BigInteger divisor = BigInteger(10);
+    for (int i = 1; i < diff; i++) {
+        divisor = divisor * BigInteger(10);
+    }
+
+    BigInteger rounded = unscaledValue_ / divisor;
+    return BigDecimal(rounded, scale);
+}
+
+std::ostream& operator<<(std::ostream& os, const BigDecimal& bd) {
+    return os << bd.toString();
+}
+
+std::istream& operator>>(std::istream& is, BigDecimal& bd) {
+    std::string str;
+    is >> str;
+    bd = BigDecimal(str);
+    return is;
+}
+
+} // namespace bstl

src/big_integer.cpp

@@ -0,0 +1,389 @@
+#include <bstl/big_integer.hpp>
+
+#include <algorithm>
+#include <stdexcept>
+#include <string>
+#include <vector>
+
+namespace bstl {
+
+std::string BigInteger::trimLeadingZeros(const std::string& value) {
+    size_t pos = 0;
+    while (pos < value.size() - 1 && value[pos] == '0') {
+        pos++;
+    }
+    return value.substr(pos);
+}
+
+int BigInteger::compareAbs(const std::string& a, const std::string& b) {
+    std::string ta = trimLeadingZeros(a);
+    std::string tb = trimLeadingZeros(b);
+    if (ta.size() != tb.size()) {
+        return ta.size() < tb.size() ? -1 : 1;
+    }
+    return ta.compare(tb) < 0 ? -1 : (ta.compare(tb) > 0 ? 1 : 0);
+}
+
+std::string BigInteger::addAbs(const std::string& a, const std::string& b) {
+    std::string result;
+    int carry = 0;
+    int i = static_cast<int>(a.size()) - 1;
+    int j = static_cast<int>(b.size()) - 1;
+    while (i >= 0 || j >= 0 || carry) {
+        int sum = carry;
+        if (i >= 0) sum += a[i--] - '0';
+        if (j >= 0) sum += b[j--] - '0';
+        result = char('0' + sum % 10) + result;
+        carry = sum / 10;
+    }
+    return result;
+}
+
+std::string BigInteger::subAbs(const std::string& a, const std::string& b) {
+    std::string ta = trimLeadingZeros(a);
+    std::string tb = trimLeadingZeros(b);
+    if (compareAbs(ta, tb) < 0) {
+        return subAbs(tb, ta);
+    }
+    std::string result;
+    int borrow = 0;
+    int i = static_cast<int>(ta.size()) - 1;
+    int j = static_cast<int>(tb.size()) - 1;
+    while (i >= 0) {
+        int diff = (ta[i--] - '0') - borrow;
+        if (j >= 0) {
+            diff -= (tb[j--] - '0');
+        }
+        if (diff < 0) {
+            diff += 10;
+            borrow = 1;
+        } else {
+            borrow = 0;
+        }
+        result = char('0' + diff) + result;
+    }
+    return trimLeadingZeros(result);
+}
+
+std::string BigInteger::mulAbs(const std::string& a, const std::string& b) {
+    std::string ta = trimLeadingZeros(a);
+    std::string tb = trimLeadingZeros(b);
+    if (ta == "0" || tb == "0") return "0";
+
+    std::vector<int> product(ta.size() + tb.size(), 0);
+    for (size_t i = 0; i < ta.size(); i++) {
+        for (size_t j = 0; j < tb.size(); j++) {
+            int mul = (ta[ta.size() - 1 - i] - '0') * (tb[tb.size() - 1 - j] - '0');
+            product[i + j] += mul;
+        }
+    }
+
+    int carry = 0;
+    for (size_t i = 0; i < product.size(); i++) {
+        int sum = product[i] + carry;
+        product[i] = sum % 10;
+        carry = sum / 10;
+    }
+
+    std::string result;
+    for (int i = static_cast<int>(product.size()) - 1; i >= 0; i--) {
+        result += char('0' + product[i]);
+    }
+    return trimLeadingZeros(result);
+}
+
+std::string BigInteger::divAbs(const std::string& a, const std::string& b) {
+    std::string tb = trimLeadingZeros(b);
+    if (tb == "0") {
+        throw std::invalid_argument("division by zero");
+    }
+    std::string ta = trimLeadingZeros(a);
+    if (compareAbs(ta, tb) < 0) {
+        return "0";
+    }
+
+    std::string quotient;
+    std::string current;
+    for (char digit : ta) {
+        current += digit;
+        current = trimLeadingZeros(current);
+        int count = 0;
+        while (compareAbs(current, tb) >= 0) {
+            current = subAbs(current, tb);
+            count++;
+        }
+        quotient += char('0' + count);
+    }
+    return trimLeadingZeros(quotient);
+}
+
+BigInteger::BigInteger() : digits_("0"), sign_(0) {}
+
+BigInteger::BigInteger(int value) : digits_("0"), sign_(1) {
+    if (value == 0) {
+        digits_ = "0";
+        sign_ = 0;
+        return;
+    }
+    if (value < 0) {
+        sign_ = -1;
+        value = -value;
+    }
+    digits_.clear();
+    while (value > 0) {
+        digits_ = char('0' + value % 10) + digits_;
+        value /= 10;
+    }
+}
+
+BigInteger::BigInteger(long long value) : digits_("0"), sign_(1) {
+    if (value == 0) {
+        digits_ = "0";
+        sign_ = 0;
+        return;
+    }
+    if (value < 0) {
+        sign_ = -1;
+        value = -value;
+    }
+    digits_.clear();
+    while (value > 0) {
+        digits_ = char('0' + value % 10) + digits_;
+        value /= 10;
+    }
+}
+
+BigInteger::BigInteger(unsigned long long value) : digits_("0"), sign_(1) {
+    if (value == 0) {
+        digits_ = "0";
+        sign_ = 0;
+        return;
+    }
+    digits_.clear();
+    while (value > 0) {
+        digits_ = char('0' + value % 10) + digits_;
+        value /= 10;
+    }
+}
+
+BigInteger::BigInteger(const std::string& value) : digits_("0"), sign_(1) {
+    if (value.empty()) {
+        digits_ = "0";
+        sign_ = 0;
+        return;
+    }
+
+    std::string text = value;
+    sign_ = 1;
+
+    if (text[0] == '-') {
+        sign_ = -1;
+        text = text.substr(1);
+    } else if (text[0] == '+') {
+        text = text.substr(1);
+    }
+
+    if (text.empty()) {
+        digits_ = "0";
+        sign_ = 0;
+        return;
+    }
+
+    for (char ch : text) {
+        if (ch < '0' || ch > '9') {
+            throw std::invalid_argument("BigInteger: invalid numeric string");
+        }
+    }
+
+    digits_ = trimLeadingZeros(text);
+    if (digits_ == "0") {
+        sign_ = 0;
+    }
+}
+
+BigInteger::BigInteger(const char* value)
+    : BigInteger(value == nullptr ? std::string("0") : std::string(value)) {}
+
+bool BigInteger::isZero() const {
+    return sign_ == 0 || digits_ == "0";
+}
+
+int BigInteger::sign() const {
+    return isZero() ? 0 : sign_;
+}
+
+std::string BigInteger::toString() const {
+    if (isZero()) return "0";
+    return (sign_ < 0 ? "-" : "") + digits_;
+}
+
+bool BigInteger::operator==(const BigInteger& other) const {
+    if (isZero() && other.isZero()) return true;
+    return sign_ == other.sign_ && digits_ == other.digits_;
+}
+
+bool BigInteger::operator!=(const BigInteger& other) const {
+    return !(*this == other);
+}
+
+bool BigInteger::operator<(const BigInteger& other) const {
+    if (sign_ != other.sign_) return sign_ < other.sign_;
+    if (sign_ == 0) return false;
+    int cmp = compareAbs(digits_, other.digits_);
+    return sign_ > 0 ? cmp < 0 : cmp > 0;
+}
+
+bool BigInteger::operator>(const BigInteger& other) const {
+    return other < *this;
+}
+
+bool BigInteger::operator<=(const BigInteger& other) const {
+    return *this < other || *this == other;
+}
+
+bool BigInteger::operator>=(const BigInteger& other) const {
+    return other <= *this;
+}
+
+bool BigInteger::operator==(int value) const {
+    return *this == BigInteger(value);
+}
+
+bool BigInteger::operator!=(int value) const {
+    return !(*this == value);
+}
+
+bool BigInteger::operator<(int value) const {
+    return *this < BigInteger(value);
+}
+
+bool BigInteger::operator>(int value) const {
+    return *this > BigInteger(value);
+}
+
+bool BigInteger::operator<=(int value) const {
+    return *this <= BigInteger(value);
+}
+
+bool BigInteger::operator>=(int value) const {
+    return *this >= BigInteger(value);
+}
+
+bool BigInteger::operator==(long long value) const {
+    return *this == BigInteger(value);
+}
+
+bool BigInteger::operator!=(long long value) const {
+    return !(*this == value);
+}
+
+bool BigInteger::operator<(long long value) const {
+    return *this < BigInteger(value);
+}
+
+bool BigInteger::operator>(long long value) const {
+    return *this > BigInteger(value);
+}
+
+bool BigInteger::operator<=(long long value) const {
+    return *this <= BigInteger(value);
+}
+
+bool BigInteger::operator>=(long long value) const {
+    return *this >= BigInteger(value);
+}
+
+BigInteger BigInteger::operator+() const {
+    return *this;
+}
+
+BigInteger BigInteger::operator-() const {
+    if (isZero()) return BigInteger(0);
+    BigInteger result(*this);
+    result.sign_ = -result.sign_;
+    return result;
+}
+
+BigInteger& BigInteger::operator+=(const BigInteger& other) {
+    *this = *this + other;
+    return *this;
+}
+
+BigInteger& BigInteger::operator-=(const BigInteger& other) {
+    *this = *this - other;
+    return *this;
+}
+
+BigInteger& BigInteger::operator*=(const BigInteger& other) {
+    *this = *this * other;
+    return *this;
+}
+
+BigInteger& BigInteger::operator/=(const BigInteger& other) {
+    *this = *this / other;
+    return *this;
+}
+
+BigInteger BigInteger::operator+(const BigInteger& other) const {
+    if (isZero()) return other;
+    if (other.isZero()) return *this;
+
+    BigInteger result;
+    if (sign_ == other.sign_) {
+        result.digits_ = addAbs(digits_, other.digits_);
+        result.sign_ = sign_;
+    } else {
+        int cmp = compareAbs(digits_, other.digits_);
+        if (cmp == 0) {
+            result.digits_ = "0";
+            result.sign_ = 0;
+        } else if (cmp > 0) {
+            result.digits_ = subAbs(digits_, other.digits_);
+            result.sign_ = sign_;
+        } else {
+            result.digits_ = subAbs(other.digits_, digits_);
+            result.sign_ = other.sign_;
+        }
+    }
+    if (result.digits_ == "0") result.sign_ = 0;
+    return result;
+}
+
+BigInteger BigInteger::operator-(const BigInteger& other) const {
+    return *this + (-other);
+}
+
+BigInteger BigInteger::operator*(const BigInteger& other) const {
+    if (isZero() || other.isZero()) return BigInteger(0);
+    BigInteger result;
+    result.digits_ = mulAbs(digits_, other.digits_);
+    result.sign_ = (sign_ * other.sign_);
+    if (result.digits_ == "0") result.sign_ = 0;
+    return result;
+}
+
+BigInteger BigInteger::operator/(const BigInteger& other) const {
+    if (other.isZero()) {
+        throw std::invalid_argument("division by zero");
+    }
+    if (isZero()) return BigInteger(0);
+    BigInteger result;
+    result.digits_ = divAbs(digits_, other.digits_);
+    result.sign_ = (sign_ * other.sign_);
+    if (result.digits_ == "0") result.sign_ = 0;
+    return result;
+}
+
+std::ostream& operator<<(std::ostream& os, const BigInteger& bi) {
+    return os << bi.toString();
+}
+
+std::istream& operator>>(std::istream& is, BigInteger& bi) {
+    std::string str;
+    is >> str;
+    bi = BigInteger(str);
+    return is;
+}
+
+} // namespace bstl
+

src/string.cpp

@@ -0,0 +1,373 @@
+#include "bstl/string.hpp"
+
+#include <sstream>
+#include <stdexcept>
+
+namespace bstl {
+
+String::String() : data_("") {}
+
+String::String(const std::string& str) : data_(str) {}
+
+String::String(const char* str) : data_(str == nullptr ? "" : str) {}
+
+std::string String::str() const {
+    return data_;
+}
+
+const char* String::c_str() const {
+    return data_.c_str();
+}
+
+size_t String::length() const {
+    return data_.length();
+}
+
+size_t String::size() const {
+    return data_.size();
+}
+
+bool String::empty() const {
+    return data_.empty();
+}
+
+char String::at(size_t pos) const {
+    if (pos >= data_.size()) {
+        throw std::out_of_range("String::at: index out of range");
+    }
+    return data_[pos];
+}
+
+char String::operator[](size_t pos) const {
+    return data_[pos];
+}
+
+char& String::operator[](size_t pos) {
+    return data_[pos];
+}
+
+std::vector<String> String::split(const String& delimiter) const {
+    std::vector<String> result;
+    
+    if (data_.empty()) {
+        return result;
+    }
+
+    if (delimiter.empty()) {
+        result.push_back(*this);
+        return result;
+    }
+
+    size_t start = 0;
+    size_t pos = 0;
+    
+    while ((pos = data_.find(delimiter.data_, start)) != std::string::npos) {
+        result.push_back(String(data_.substr(start, pos - start)));
+        start = pos + delimiter.size();
+    }
+    
+    result.push_back(String(data_.substr(start)));
+    return result;
+}
+
+String String::join(const std::vector<String>& parts, const String& delimiter) {
+    if (parts.empty()) {
+        return String("");
+    }
+    
+    std::string result = parts[0].str();
+    for (size_t i = 1; i < parts.size(); i++) {
+        result += delimiter.str() + parts[i].str();
+    }
+    return String(result);
+}
+
+String String::replace(const String& oldStr, const String& newStr, int count) const {
+    if (oldStr.empty()) {
+        return *this;
+    }
+
+    std::string result = data_;
+    size_t pos = 0;
+    int replaced = 0;
+
+    while ((pos = result.find(oldStr.data_, pos)) != std::string::npos && (count < 0 || replaced < count)) {
+        result.replace(pos, oldStr.size(), newStr.str());
+        pos += newStr.size();
+        replaced++;
+    }
+
+    return String(result);
+}
+
+String String::upper() const {
+    std::string result = data_;
+    std::transform(result.begin(), result.end(), result.begin(),
+                   [](unsigned char c) { return std::toupper(c); });
+    return String(result);
+}
+
+String String::lower() const {
+    std::string result = data_;
+    std::transform(result.begin(), result.end(), result.begin(),
+                   [](unsigned char c) { return std::tolower(c); });
+    return String(result);
+}
+
+String String::capitalize() const {
+    if (data_.empty()) {
+        return *this;
+    }
+    std::string result = data_;
+    result[0] = std::toupper(static_cast<unsigned char>(result[0]));
+    for (size_t i = 1; i < result.size(); i++) {
+        result[i] = std::tolower(static_cast<unsigned char>(result[i]));
+    }
+    return String(result);
+}
+
+String String::title() const {
+    std::string result = data_;
+    bool newWord = true;
+    for (size_t i = 0; i < result.size(); i++) {
+        if (std::isspace(static_cast<unsigned char>(result[i]))) {
+            newWord = true;
+        } else {
+            if (newWord) {
+                result[i] = std::toupper(static_cast<unsigned char>(result[i]));
+                newWord = false;
+            } else {
+                result[i] = std::tolower(static_cast<unsigned char>(result[i]));
+            }
+        }
+    }
+    return String(result);
+}
+
+bool String::startswith(const String& prefix) const {
+    if (prefix.size() > data_.size()) {
+        return false;
+    }
+    return data_.compare(0, prefix.size(), prefix.data_) == 0;
+}
+
+bool String::endswith(const String& suffix) const {
+    if (suffix.size() > data_.size()) {
+        return false;
+    }
+    return data_.compare(data_.size() - suffix.size(), suffix.size(), suffix.data_) == 0;
+}
+
+bool String::contains(const String& substring) const {
+    return data_.find(substring.data_) != std::string::npos;
+}
+
+bool String::isdigit() const {
+    if (data_.empty()) return false;
+    for (unsigned char c : data_) {
+        if (!std::isdigit(c)) return false;
+    }
+    return true;
+}
+
+bool String::isalpha() const {
+    if (data_.empty()) return false;
+    for (unsigned char c : data_) {
+        if (!std::isalpha(c)) return false;
+    }
+    return true;
+}
+
+bool String::isalnum() const {
+    if (data_.empty()) return false;
+    for (unsigned char c : data_) {
+        if (!std::isalnum(c)) return false;
+    }
+    return true;
+}
+
+bool String::isspace() const {
+    if (data_.empty()) return false;
+    for (unsigned char c : data_) {
+        if (!std::isspace(c)) return false;
+    }
+    return true;
+}
+
+bool String::isupper() const {
+    if (data_.empty()) return false;
+    for (unsigned char c : data_) {
+        if (std::isalpha(c) && !std::isupper(c)) {
+            return false;
+        }
+    }
+    return true;
+}
+
+bool String::islower() const {
+    if (data_.empty()) return false;
+    for (unsigned char c : data_) {
+        if (std::isalpha(c) && !std::islower(c)) {
+            return false;
+        }
+    }
+    return true;
+}
+
+int String::find(const String& substring, size_t start) const {
+    size_t pos = data_.find(substring.data_, start);
+    return pos == std::string::npos ? -1 : static_cast<int>(pos);
+}
+
+int String::rfind(const String& substring) const {
+    size_t pos = data_.rfind(substring.data_);
+    return pos == std::string::npos ? -1 : static_cast<int>(pos);
+}
+
+int String::count(const String& substring) const {
+    if (substring.empty()) return 0;
+    int count = 0;
+    size_t pos = 0;
+    while ((pos = data_.find(substring.data_, pos)) != std::string::npos) {
+        count++;
+        pos += substring.size();
+    }
+    return count;
+}
+
+String String::strip() const {
+    size_t start = 0;
+    size_t end = data_.size();
+
+    while (start < end && std::isspace(static_cast<unsigned char>(data_[start]))) {
+        start++;
+    }
+    while (end > start && std::isspace(static_cast<unsigned char>(data_[end - 1]))) {
+        end--;
+    }
+
+    return String(data_.substr(start, end - start));
+}
+
+String String::lstrip() const {
+    size_t start = 0;
+    while (start < data_.size() && std::isspace(static_cast<unsigned char>(data_[start]))) {
+        start++;
+    }
+    return String(data_.substr(start));
+}
+
+String String::rstrip() const {
+    size_t end = data_.size();
+    while (end > 0 && std::isspace(static_cast<unsigned char>(data_[end - 1]))) {
+        end--;
+    }
+    return String(data_.substr(0, end));
+}
+
+String String::strip(const String& chars) const {
+    size_t start = 0;
+    size_t end = data_.size();
+
+    while (start < end && chars.data_.find(data_[start]) != std::string::npos) {
+        start++;
+    }
+    while (end > start && chars.data_.find(data_[end - 1]) != std::string::npos) {
+        end--;
+    }
+
+    return String(data_.substr(start, end - start));
+}
+
+String String::ljust(size_t width, char fillchar) const {
+    if (data_.size() >= width) {
+        return *this;
+    }
+    std::string result = data_;
+    result.append(width - data_.size(), fillchar);
+    return String(result);
+}
+
+String String::rjust(size_t width, char fillchar) const {
+    if (data_.size() >= width) {
+        return *this;
+    }
+    std::string result(width - data_.size(), fillchar);
+    result.append(data_);
+    return String(result);
+}
+
+String String::center(size_t width, char fillchar) const {
+    if (data_.size() >= width) {
+        return *this;
+    }
+    size_t totalPad = width - data_.size();
+    size_t leftPad = totalPad / 2;
+    size_t rightPad = totalPad - leftPad;
+    std::string result(leftPad, fillchar);
+    result.append(data_);
+    result.append(rightPad, fillchar);
+    return String(result);
+}
+
+int String::toInt() const {
+    return std::stoi(data_);
+}
+
+long long String::toLongLong() const {
+    return std::stoll(data_);
+}
+
+double String::toDouble() const {
+    return std::stod(data_);
+}
+
+String String::operator+(const String& other) const {
+    return String(data_ + other.data_);
+}
+
+String String::operator+(const char* str) const {
+    return String(data_ + (str == nullptr ? "" : str));
+}
+
+String& String::operator+=(const String& other) {
+    data_ += other.data_;
+    return *this;
+}
+
+bool String::operator==(const String& other) const {
+    return data_ == other.data_;
+}
+
+bool String::operator!=(const String& other) const {
+    return data_ != other.data_;
+}
+
+bool String::operator<(const String& other) const {
+    return data_ < other.data_;
+}
+
+bool String::operator>(const String& other) const {
+    return data_ > other.data_;
+}
+
+bool String::operator<=(const String& other) const {
+    return data_ <= other.data_;
+}
+
+bool String::operator>=(const String& other) const {
+    return data_ >= other.data_;
+}
+
+std::ostream& operator<<(std::ostream& os, const String& str) {
+    return os << str.str();
+}
+
+std::istream& operator>>(std::istream& is, String& str) {
+    std::string temp;
+    is >> temp;
+    str = String(temp);
+    return is;
+}
+
+} // namespace bstl

tests/IOTest.cpp

@@ -0,0 +1,64 @@
+#include <bstl/big_integer.hpp>
+#include <bstl/big_decimal.hpp>
+#include <bstl/string.hpp>
+
+#include <sstream>
+#include <cassert>
+#include <iostream>
+
+int main() {
+    using bstl::BigInteger;
+    using bstl::BigDecimal;
+    using bstl::String;
+
+    // 测试 BigInteger 的 cout
+    BigInteger bi1("12345678901234567890");
+    std::ostringstream oss1;
+    oss1 << bi1;
+    assert(oss1.str() == "12345678901234567890");
+
+    // 测试 BigInteger 的 cin
+    std::istringstream iss1("987654321");
+    BigInteger bi2;
+    iss1 >> bi2;
+    assert(bi2.toString() == "987654321");
+
+    // 测试负数
+    std::istringstream iss2("-555");
+    BigInteger bi3;
+    iss2 >> bi3;
+    assert(bi3.toString() == "-555");
+
+    // 测试 BigDecimal 的 cout
+    BigDecimal bd1("123.45");
+    std::ostringstream oss2;
+    oss2 << bd1;
+    assert(oss2.str() == "123.45");
+
+    // 测试 BigDecimal 的 cin
+    std::istringstream iss3("67.89");
+    BigDecimal bd2;
+    iss3 >> bd2;
+    assert(bd2.toString() == "67.89");
+
+    // 测试负小数
+    std::istringstream iss4("-12.34");
+    BigDecimal bd3;
+    iss4 >> bd3;
+    assert(bd3.toString() == "-12.34");
+
+    // 测试 String 的 cout
+    String s1("Hello World");
+    std::ostringstream oss3;
+    oss3 << s1;
+    assert(oss3.str() == "Hello World");
+
+    // 测试 String 的 cin
+    std::istringstream iss5("HelloWorld");
+    String s2;
+    iss5 >> s2;
+    assert(s2.str() == "HelloWorld");
+
+    std::cout << "All cin/cout tests passed!\n";
+    return 0;
+}

tests/StringTest.cpp

@@ -0,0 +1,107 @@
+#include <bstl/string.hpp>
+
+#include <cassert>
+#include <iostream>
+
+int main() {
+    using bstl::String;
+
+    // 基本构造和获取
+    String s1("Hello, World!");
+    assert(s1.length() == 13);
+    assert(s1.c_str() == std::string("Hello, World!"));
+
+    // split 分割
+    String s2("apple,banana,cherry");
+    auto parts = s2.split(",");
+    assert(parts.size() == 3);
+    assert(parts[0] == String("apple"));
+    assert(parts[1] == String("banana"));
+    assert(parts[2] == String("cherry"));
+
+    // join 连接
+    std::vector<String> words = {String("Hello"), String("World")};
+    String joined = String::join(words, " ");
+    assert(joined == String("Hello World"));
+
+    // replace 替换
+    String s3("hello hello world");
+    String replaced = s3.replace("hello", "hi");
+    assert(replaced == String("hi hi world"));
+
+    String replaced1 = s3.replace("hello", "hi", 1);
+    assert(replaced1 == String("hi hello world"));
+
+    // upper/lower
+    String s4("HeLLo WoRLd");
+    assert(s4.upper() == String("HELLO WORLD"));
+    assert(s4.lower() == String("hello world"));
+
+    // capitalize
+    String s5("hello");
+    assert(s5.capitalize() == String("Hello"));
+
+    // title
+    String s6("hello world");
+    assert(s6.title() == String("Hello World"));
+
+    // startswith/endswith
+    String s7("hello.txt");
+    assert(s7.startswith("hello"));
+    assert(s7.endswith(".txt"));
+    assert(!s7.startswith(".txt"));
+
+    // contains
+    assert(s7.contains("llo"));
+    assert(!s7.contains("xyz"));
+
+    // isdigit/isalpha/isalnum
+    assert(String("12345").isdigit());
+    assert(!String("123a").isdigit());
+    assert(String("abc").isalpha());
+    assert(!String("abc1").isalpha());
+    assert(String("abc123").isalnum());
+
+    // isupper/islower
+    assert(String("HELLO").isupper());
+    assert(String("hello").islower());
+    assert(!String("Hello").isupper());
+
+    // find/rfind/count
+    assert(s2.find("banana") == 6);
+    assert(s2.find("xyz") == -1);
+    assert(s3.count("hello") == 2);
+
+    // strip
+    String s8("  hello world  ");
+    assert(s8.strip() == String("hello world"));
+    assert(s8.lstrip() == String("hello world  "));
+    assert(s8.rstrip() == String("  hello world"));
+
+    // ljust/rjust/center
+    String s9("hi");
+    assert(s9.ljust(5, '.') == String("hi..."));
+    assert(s9.rjust(5, '.') == String("...hi"));
+    assert(s9.center(5, '.') == String(".hi.."));
+
+    // 字符串转换
+    assert(String("123").toInt() == 123);
+    assert(String("456789").toLongLong() == 456789);
+    assert(String("3.14").toDouble() == 3.14);
+
+    // 运算符
+    String sa("Hello");
+    String sb(" World");
+    String sc = sa + sb;
+    assert(sc == String("Hello World"));
+
+    sa += sb;
+    assert(sa == String("Hello World"));
+
+    // 比较
+    assert(String("abc") < String("def"));
+    assert(String("xyz") > String("abc"));
+
+    std::cout << "All String tests passed!\n";
+    return 0;
+}

tests/big_decimal_test.cpp

@@ -0,0 +1,41 @@
+#include <bstl/big_decimal.hpp>
+
+#include <cassert>
+#include <iostream>
+#include <string>
+
+int main() {
+    using bstl::BigDecimal;
+
+    // 基本构造
+    BigDecimal a("123.45");
+    BigDecimal b("67.89");
+    BigDecimal c = a + b;
+
+    assert(c.toString() == "191.34");
+
+    // 减法
+    BigDecimal d = a - b;
+    assert(d.toString() == "55.56");
+
+    // 乘法
+    BigDecimal e = a * BigDecimal("2");
+    assert(e.toString() == "246.90");
+
+    // 比较
+    assert((a > b) == true);
+    assert((a == a) == true);
+    assert((a != b) == true);
+
+    // 零
+    BigDecimal zero("0.0");
+    assert(zero.isZero());
+
+    // 负数
+    BigDecimal neg("-100.50");
+    assert(neg.sign() < 0);
+    assert((-neg).toString() == "100.50");
+
+    std::cout << "BigDecimal tests passed\n";
+    return 0;
+}

tests/big_integer_test.cpp

@@ -0,0 +1,31 @@
+#include <bstl/big_integer.hpp>
+
+#include <cassert>
+#include <iostream>
+#include <string>
+
+int main() {
+    using bstl::BigInteger;
+
+    BigInteger a("12345678901234567890");
+    BigInteger b("98765432109876543210");
+    BigInteger c = a + b;
+    BigInteger d = b - a;
+    BigInteger e = a * BigInteger("2");
+    BigInteger f = BigInteger("100000000000000000000000") / BigInteger("1000000000000000000");
+
+    assert(c.toString() == "111111111011111111100");
+    assert(d.toString() == "86419753208641975320");
+    assert(e.toString() == "24691357802469135780");
+    assert(f.toString() == "100000");
+
+    BigInteger zero("0");
+    assert((a == a) == true);
+    assert((a != b) == true);
+    assert((zero == 0) == true);
+    assert((a > BigInteger("12345678901234567889")) == true);
+    assert((a < b) == true);
+
+    std::cout << "BigInteger tests passed\n";
+    return 0;
+}