c++ lambda函数

c++ lambda函数能够提升性能，减少函数开销
例子如下：

#include 
#include 
using namespace std;

#define N 10000000

void test(){
    for(int i = 0; i < N; i++){}
}

int main(){
    clock_t start, end;

    start = clock();
    test();
    end = clock();
    cout << "regular time:" << (double)(end - start) / CLOCKS_PER_SEC << endl;

    start = clock();
    [](){for(int i = 0; i < N; i++); return;};
    end = clock();
    cout << "lambda time: " << (double)(end - start) / CLOCKS_PER_SEC << endl;
}

相关结果：

regular time:0.004946
lambda time: 1e-06

可见，c++ lambda函数能够明显提升速度