C++11--------vector

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本文深入探讨了C++标准库中vector容器的使用方法，包括初始化、元素插入与访问、迭代器应用、内存管理等核心操作，并通过实例展示了如何正确地进行资源释放。

1.vector的赋值，迭代器访问，内存释放等

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#include <iostream>
#include <vector>

using namespace std;

void main()
{

vector<int> vec={1,2,3,4,5,6,7,8};
vec.push_back(9);
vec.insert(vec.begin(),0);

cout<<"vector loop:"<<endl;

for(int i=0;i<vec.size();i++)
{
cout<<vec[i]<<",";
}
cout<<"\n"<<endl;

cout<<"itor loop::"<<endl;
vector<int>::iterator itor1= vec.begin();
for(itor1=vec.begin();itor1<vec.end();itor1++)
{
cout<<"itor1::"<<*itor1<<endl;
}

cout<<"vector size::"<<vec.size()<<endl;

// c++ standard lib useing
cout<<"**********c++ standard lib using*******"<<endl;
vector<int>ivec;
vector<int>::iterator iter=ivec.end();
for(int i=0;i!=10;++i)
{
      ivec.insert(iter,i); //在指定位置iter前插入值为的元素,返回指向这个元素的迭代器,
      iter=ivec.end();
}
for(iter=ivec.begin();iter<ivec.end();iter++)
{
      cout<<"c++ standard lib itor1::"<<*iter<<endl;
}

vector<int>ivec5;
//vector<int>::iterator itor2;
for(int cnt =0;cnt<10;++cnt)
{
ivec5.push_back(cnt); //push_back()添加值为的元素到当前vector末尾
}
for(auto itor2=ivec5.begin();itor2<ivec5.end();itor2++)
{
cout<<"c++ standard lib itor2::"<<*itor2<<endl;
}

cout<<"c++ standard lib ::set vec pointer\n"<<endl;
vector<int *> v;
// set value
for(int i=0;i<10;i++)
{
      int *p= new(int);
      *p=i;
      v.push_back(p);

}
// access the member of vec
for (vector<int *>::iterator it = v.begin(); it != v.end(); it ++)
{

cout<<**it<<" "<<endl; //*it 指向迭代器的所指元素的引用

}

cout<<"free itor member size:"<<v.size()<<endl;
for (vector<int *>::iterator it1 = v.begin(); it1 != v.end(); it1 ++)
{
      cout<<"free address[value]:"<<*it1<<"["<<**it1<<"]"<<",vec.size="<<v.size()<<endl;
      if (NULL != *it1)
      {
          delete *it1;
          *it1 = NULL;
      }
}

if(!v.empty())
{
      cout<<"begin to clear vector!!"<<endl;
      v.clear();
}
if(v.empty())
{
     cout<<"clear the vector completely!!"<<endl;
}

}