diff --git a/CMakeLists.txt b/CMakeLists.txt
index fa21fe4..8656933 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -42,6 +42,11 @@ 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
diff --git a/IO_SUPPORT.md b/IO_SUPPORT.md
new file mode 100644
index 0000000..eddd0c3
--- /dev/null
+++ b/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
+```
diff --git a/examples/IODemo.cpp b/examples/IODemo.cpp
new file mode 100644
index 0000000..8800568
--- /dev/null
+++ b/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;
+}
diff --git a/examples/a.out b/examples/a.out
new file mode 100755
index 0000000..978346a
Binary files /dev/null and b/examples/a.out differ
diff --git a/include/bstl/big_decimal.hpp b/include/bstl/big_decimal.hpp
index 59b8639..0ce87b6 100644
--- a/include/bstl/big_decimal.hpp
+++ b/include/bstl/big_decimal.hpp
@@ -2,6 +2,7 @@
 #define BETTERSTL_BIG_DECIMAL_H
 
 #include <string>
+#include <iostream>
 #include <bstl/big_integer.hpp>
 
 namespace bstl {
@@ -69,6 +70,10 @@ private:
                           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
diff --git a/include/bstl/big_integer.hpp b/include/bstl/big_integer.hpp
index c4f12d9..2f6e088 100644
--- a/include/bstl/big_integer.hpp
+++ b/include/bstl/big_integer.hpp
@@ -2,6 +2,7 @@
 #define BETTERSTL_BIG_INTEGER_HPP
 
 #include <string>
+#include <iostream>
 
 namespace bstl {
 
@@ -65,6 +66,10 @@ private:
     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
diff --git a/include/bstl/string.hpp b/include/bstl/string.hpp
index 1253201..37588fe 100644
--- a/include/bstl/string.hpp
+++ b/include/bstl/string.hpp
@@ -4,6 +4,7 @@
 #include <vector>
 #include <algorithm>
 #include <cctype>
+#include <iostream>
 
 namespace bstl {
 
@@ -89,4 +90,8 @@ 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
diff --git a/src/big_decimal.cpp b/src/big_decimal.cpp
index 52291ee..2570da5 100644
--- a/src/big_decimal.cpp
+++ b/src/big_decimal.cpp
@@ -338,4 +338,15 @@ BigDecimal BigDecimal::round(int scale) const {
     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
diff --git a/src/big_integer.cpp b/src/big_integer.cpp
index 3ed86c3..4436fd9 100644
--- a/src/big_integer.cpp
+++ b/src/big_integer.cpp
@@ -374,5 +374,16 @@ BigInteger BigInteger::operator/(const BigInteger& other) const {
     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
 
diff --git a/src/string.cpp b/src/string.cpp
index 0c8b784..e1e2a1a 100644
--- a/src/string.cpp
+++ b/src/string.cpp
@@ -359,4 +359,15 @@ 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
diff --git a/tests/IOTest.cpp b/tests/IOTest.cpp
new file mode 100644
index 0000000..eae9339
--- /dev/null
+++ b/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;
+}