Qt与STL容器效率比较

Qt与STL容器效率比较

测试平台：windows10 Intel 7700HQ
编译器:MSVC2017*64 -O2

vector

插入500000000个int值并删除，测试运行时间，代码如下：

#include "mainwindow.h"
#include <iostream>
#include <QApplication>
#include <vector>
#include <QVector>
#include <windows.h>
std::vector<int> stl;
QVector<int> Qtv;
int main(int argc, char *argv[]) {
    LARGE_INTEGER beg,ed,freq;
    std::cout<<"begin test!"<<std::endl;
    QueryPerformanceFrequency(&freq);
    QueryPerformanceCounter(&beg);
    for(int i = 1; i<=500000000; i++) {
        stl.push_back(i);
    }
    stl.clear();
    QueryPerformanceCounter(&ed);
    double duration = (double)(ed.QuadPart-beg.QuadPart)/(double)freq.QuadPart;
    std::cout<<"std:"<<duration<<std::endl;
    QueryPerformanceCounter(&beg);
    for(int i = 1; i<=500000000; i++) {
        Qtv.push_back(i);
    }
    Qtv.clear();
    QueryPerformanceCounter(&ed);
    duration = (double)(ed.QuadPart-beg.QuadPart)/(double)freq.QuadPart;
    std::cout<<"Qt:"<<duration<<std::endl;
    return 0;
}

结果:单位：s

项目	测试1	测试2	测试3
stl	4.49656	4.26468	4.30204
qt	4.69023	4.74365	4.69194
如果是1000000000的数据量的话STL需要7.5s，而Qt会直接卡死。综上来看，stl的vector效率高于QVector。

set

插入50000000组数据，比较时间,代码：

#include "mainwindow.h"
#include <iostream>
#include <QApplication>
#include <set>
#include <QSet>
#include <cstdlib>
#include <windows.h>
std::set<int> stl;
QSet<int> Qtset;
int main(int argc, char *argv[]) {
    LARGE_INTEGER beg,ed,freq;
    std::cout<<"begin test!"<<std::endl;
    QueryPerformanceFrequency(&freq);
    QueryPerformanceCounter(&beg);
    for(int i = 1; i<=50000000; i++) {
        stl.insert(i);
    }
    stl.clear();
    QueryPerformanceCounter(&ed);
    double duration = (double)(ed.QuadPart-beg.QuadPart)/(double)freq.QuadPart;
    std::cout<<"std:"<<duration<<std::endl;
    QueryPerformanceCounter(&beg);
    for(int i = 1; i<=50000000; i++) {
        Qtset.insert(i);
    }
    Qtset.clear();
    QueryPerformanceCounter(&ed);
    duration = (double)(ed.QuadPart-beg.QuadPart)/(double)freq.QuadPart;
    std::cout<<"Qt:"<<duration<<std::endl;
    return 0;
}

项目	测试1	测试2	测试3
stl	13.8065	12.876	12.6713
qt	6.56534	6.13544	6.20306
可见，QSet效率远高于STL.