STL::vector

在vector中查找元素及其位置

#include "stdafx.h"
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;


int main()
{
    // A dynamic array of integers
    vector <int> vecIntegerArray;

    //Insert sample integers into the array
    vecIntegerArray.push_back(50);
    vecIntegerArray.push_back(2991);
    vecIntegerArray.push_back(23);
    vecIntegerArray.push_back(9999);

    cout << "The contents of the vector are:" << endl;

    //Walk the vector and read values using an interator
    vector <int>::iterator iArrayWalker = vecIntegerArray.begin();
    //聲明迭代器對象iArrayWalker，並將其初始化爲指向容器開頭，即vector的成員函數begin()返回的值。

    while (iArrayWalker != vecIntegerArray.end())
    {
        //Write the value to the screen
        cout << *iArrayWalker << endl;
        //Increment the iterator to access the next element
        ++iArrayWalker;
    }

    //Find an element(say 2991)in the array using the 'find' algorithm...
    **vector <int>::iterator iElement = find(vecIntegerArray.begin(), vecIntegerArray.end(), 2991);**
//find操作的結果也是一個迭代器，通過將迭代器與容器末尾進行比較，可判斷find是否成功
    //Check if value was found
    if (iElement != vecIntegerArray.end())
    {
        //Value was found...Determine position int array;
        int nPosition = distance(vecIntegerArray.begin(), iElement);
    //distance計算找到的元素的所處位置的偏移量。
        cout << "Value " << *iElement;
        cout << " found in the vector at position:" << nPosition << endl;
    }
    getchar();
    return 0;
}