编辑“︁C++ raii 原则”︁（章节）

== 代码示例 ==

=== 基本示例 ===
以下是一个简单的RAII示例，展示如何使用RAII管理动态内存：

<syntaxhighlight lang="cpp">
#include <iostream>
#include <memory>

class RAIIExample {
private:
    int* data;
public:
    // 构造函数：获取资源
    RAIIExample(size_t size) {
        data = new int[size];
        std::cout << "Resource allocated (size: " << size << ")\n";
    }

    // 析构函数：释放资源
    ~RAIIExample() {
        delete[] data;
        std::cout << "Resource freed\n";
    }

    void useResource() {
        std::cout << "Using the resource\n";
    }
};

int main() {
    {
        RAIIExample obj(10); // 资源在构造函数中分配
        obj.useResource();
    } // obj离开作用域，析构函数自动调用，资源释放

    return 0;
}
</syntaxhighlight>

'''输出：'''
<pre>
Resource allocated (size: 10)
Using the resource
Resource freed
</pre>

=== 异常安全示例 ===
RAII在异常发生时仍能保证资源释放：

<syntaxhighlight lang="cpp">
#include <iostream>
#include <stdexcept>

class FileHandler {
private:
    FILE* file;
public:
    FileHandler(const char* filename) {
        file = fopen(filename, "r");
        if (!file) throw std::runtime_error("Failed to open file");
        std::cout << "File opened\n";
    }

    ~FileHandler() {
        if (file) {
            fclose(file);
            std::cout << "File closed\n";
        }
    }

    void readFile() {
        throw std::runtime_error("Simulated error during read");
    }
};

int main() {
    try {
        FileHandler handler("example.txt");
        handler.readFile(); // 抛出异常
    } catch (const std::exception& e) {
        std::cerr << "Error: " << e.what() << '\n';
    }
    return 0;
}
</syntaxhighlight>

'''输出：'''
<pre>
File opened
File closed
Error: Simulated error during read
</pre>