Qt與STL容器效率比較

測試平臺：windows10 Intel 7700HQ
編譯器:MSVC2017*64 -O2

vector

插入500000000個int值並刪除，測試執行時間，程式碼如下：

#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;
}

 

結果:單位：s

如果是1000000000的資料量的話STL需要7.5s，而Qt會直接卡死。綜上來看，stl的vector效率高於QVector。

set

插入50000000組資料，比較時間,程式碼：

#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;
}

 

可見，QSet效率遠高於STL.