std::vector的一些使用注意事項

• 使用at()函數而不是operator[]：理由是at()可以拋出invalid vector[T] subscript異常，而operator[]不會做範圍檢查。因此，at()函數更加安全。
• 使用vector的assign函數複製一個vector:

include "stdafx.h"#include <vector>#include <iostream>int main( ){using namespace std;vector<int> v1, v2, v3;vector<int>::iterator iter;v1.push_back(10);v1.push_back(20);v1.push_back(30);v1.push_back(40);v1.push_back(50);cout << "v1 = " ;for (iter = v1.begin(); iter != v1.end(); iter++)cout << *iter << " ";cout << endl;v2.assign(v1.begin(), v1.end());cout << "v2 = ";for (iter = v2.begin(); iter != v2.end(); iter++)cout << *iter << " ";cout << endl;v3.assign(7, 4) ;cout << "v3 = ";for (iter = v3.begin(); iter != v3.end(); iter++)cout << *iter << " ";cout << endl;}