vetcor的基本操作

#include <iostream>
#include <vector>
using namespace std;


int main()
{
    //vector初始化方法
    vector<int> v1; //声明空vector对象
    vector<int> v2(10, 0);//10个0
    vector<int> v3{ 0, 1, 2, 3, 4, 5, 6 };
    vector<int> v4;
    //向vector中添加对象
    for (int i = 0; i<10; ++i)
    {
        v1.push_back(i);
    }

    //检查vector是否为空对象
    if (v1.empty())
    {
        cout << "v1 is empty!" << endl;
    }
    else
    {
        cout << "v1 has " << v1.size() << " elements" << endl;//使用size成员函数返回vector中元素的个数
    }

    v4 = v3;//vector可以进行赋值操作

    if (v3 == v4)//vector的关系运算
    {
        cout << "v3==v4" << endl;
    }
    //vector对象的输出
    for (auto i : v1)//表达方法1
        cout << i << " ";
    cout << endl;
    for (vector<int>::const_iterator beg = v1.begin(); beg != v1.end(); ++beg)//方法2
    {
        cout << *beg <<" ";
    }
    cout << endl;

    cout << "v2 value:" << endl;
    for (auto i : v2)//表达方法1
        cout << i << " ";
    cout << endl;
    cout << "v3value:" << endl;
    for (auto i : v3)//表达方法1
        cout << i << " ";
    cout << endl;
    cout << "v4 value:" << endl;
    for (auto i : v4)//表达方法1
        cout << i << " ";
    cout << endl;
    return 0;
}

vector<int> ivec;//空vector对象
for (decltype(ivec.size()) ix = 0; ix != 10; ++ix)
    ivec[ix] = ix;//严重错误