C++ 匿名函数与函数对象的性能比较

// 匿名函数
auto lambda = [](int n) {
    int sum = 0;
    for (int i = 0; i <= n; i++) {
        sum += i;
    }
    return sum;
};

// 函数对象
struct Sum {
    int operator()(int n) {
        int sum = 0;
        for (int i = 0; i <= n; i++) {
            sum += i;
        }
        return sum;
    }
};

// 主函数
int main() {
    int n = 100000000;
    int result;
    
    // 匿名函数
    auto start = std::chrono::high_resolution_clock::now();
    result = lambda(n);
    auto end = std::chrono::high_resolution_clock::now();
    std::cout << "匿名函数运行时间：" << std::chrono::duration<double, std::milli>(end - start).count() << "毫秒" << std::endl;
    
    // 函数对象
    Sum sum;
    start = std::chrono::high_resolution_clock::now();
    result = sum(n);
    end = std::chrono::high_resolution_clock::now();
    std::cout << "函数对象运行时间：" << std::chrono::duration<double, std::milli>(end - start).count() << "毫秒" << std::endl;
    
    return 0;
}