vector＜bool＞性能测试

cpp 复制代码

#include <iostream>
#include <vector>
#include <sstream>
#include <numeric>
#include <string>
#include <unordered_map>
#include <queue>
#include <map>
using namespace std;


int main()
{
    clock_t t1, t2, t3;
    vector<bool> vb;
    vector<int> vi;
    vector<char> vc;

    t1 = clock();
    for (int i = 0; i < 1000; ++i)
    {
        for (int j = 0; j < 1000; ++j)
        {
            vb.push_back(true);
        }
    }
    t1 = clock() - t1;

    t2 = clock();
    for (int i = 0; i < 1000; ++i)
    {
        for (int j = 0; j < 1000; ++j)
        {
            vi.push_back(1);
        }
    }
    t2 = clock() - t2;

    t3 = clock();
    for (int i = 0; i < 1000; ++i)
    {
        for (int j = 0; j < 1000; ++j)
        {
            vc.push_back('a');
        }
    }
    t3 = clock() - t3;

    cout << "'vector<bool>::push_back(true)' 1000000 times cost: " << t1 << endl;
    cout << "'vector<int>::push_back(1)' 1000000 times cost: " << t2 << endl;
    cout << "'vector<char>::push_back('a')' 1000000 times cost: " << t3 << endl;

    t1 = clock();
    for (int i = 0; i < 1000; ++i)
    {
        for (int j = 0; j < 1000; ++j)
        {
            bool b = vb[j + 1000 * i];
        }
    }
    t1 = clock() - t1;

    t2 = clock();
    for (int i = 0; i < 1000; ++i)
    {
        for (int j = 0; j < 1000; ++j)
        {
            int b = vi[j + 1000 * i];
        }
    }
    t2 = clock() - t2;

    t3 = clock();
    for (int i = 0; i < 1000; ++i)
    {
        for (int j = 0; j < 1000; ++j)
        {
            char b = vc[j + 1000 * i];
        }
    }
    t3 = clock() - t3;

    cout << "'vector<bool>::operator[]' 1000000 times cost: " << t1 << endl;
    cout << "'vector<int>::operator[]' 1000000 times cost: " << t2 << endl;
    cout << "'vector<char>::operator[]' 1000000 times cost: " << t3 << endl;

    return 0;
}

测试结果

bash 复制代码

'vector<bool>::push_back(true)' 1000000 times cost: 4824
'vector<int>::push_back(1)' 1000000 times cost: 62
'vector<char>::push_back('a')' 1000000 times cost: 59
'vector<bool>::operator[]' 1000000 times cost: 312
'vector<int>::operator[]' 1000000 times cost: 5
'vector<char>::operator[]' 1000000 times cost: 6

原理：

vector<bool> 源码分析