vector向量begin()函数运用实例

begin函数

语法:

1 2	iterator begin(); const_iterator begin() const;

begin() 返回第一个元素的迭代器

源代码

// iterators

/**

* Returns a read/write iterator that points to the first

* element in the %vector. Iteration is done in ordinary

* element order.

iterator

begin() { return iterator (this->_M_impl._M_start); }

/**

* Returns a read-only (constant) iterator that points to the

* first element in the %vector. Iteration is done in ordinary

* element order.

const_iterator

begin() const { return const_iterator (this->_M_impl._M_start); }

测试代码

// 梁笔记

// https://zouzhongliang.com

#include <iostream>

#include <vector>

using namespace std;

int main()

{

vector<int> v1(5, 0);

vector<int> v2(10, 2);

vector<int>::iterator iter = v1.begin();

for(iter;iter!=v1.end();iter++){

cout<<(*iter)<<endl;

}

测试结果：