通路vector元素方法的效率比較

相信會來看這篇部落格的人，應該都認識vector了，是以我就直接上測試代碼了，我是在vs2015中測試的：

#include<iostream>
#include<vector>
#include<windows.h>
using namespace std;



int main() {
    //建立4個vector，使用清單初始化，相當與調用拷貝構造函數
    vector<int> v1;
    int temp;
    int i;
    for (i = 0; i < 100000; ++i) {
        v1.push_back(i);
    }
    //測試1
    DWORD start,end;
    start= GetTickCount();
    for (i = 0; i < v1.size(); ++i) {
        temp=v1[i];
    }
    end = GetTickCount();
    cout << "使用[]運算符耗時：" << end - start << "ms" << endl;
    //測試2
    start = GetTickCount();
    for (auto k = v1.begin(); k < v1.end(); ++k)
    {
        temp = *k;
    }
    end = GetTickCount();
    cout << "使用疊代器（++k）耗時：" << end - start << "ms" << endl;

    //測試3
    start = GetTickCount();

    for (auto k = v1.begin(); k < v1.end(); k++)
    {
        temp = *k;
    }
    end = GetTickCount();
    cout << "使用疊代器,使用k++，而不是++k：" << end - start << "ms" << endl;

    //測試4
    start = GetTickCount();
    i = 0;
    for (auto k = v1.begin(); i<v1.size(); ++i,++k)
    {
        temp = *k;
    }
    end = GetTickCount();
    cout << "使用疊代器,不使用end（）方法：" << end - start << "ms" << endl;




    system("pause");
    return 0;
}

      

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