Map是c++的一个标准容器,她提供了很好一对一的关系,在一些程序中建立一个map可以起到事半功倍的效果,总结了一些map基本简单实用的操作!
  1. map基本的构造函数;
map<string , int >mapstring;         map<int ,string >mapint;
map<sring, char>mapstring;         map< char ,string>mapchar;
map<char ,int>mapchar;            map<int ,char >mapint;
  2. map添加数据;
  map<int ,string> maplive;
  1.maplive.insert(pair<int,string>(102,"aclive"));
  2.maplive.insert(map<int,string>::value_type(321,"hai"));
  3, maplive[112]="April";//map中简单常用的插入添加!
  3,map中元素的查找:
  find()函数返回一个迭代器指向键值为key的元素,如果没找到返回指向map尾部的迭代器。
  map<int ,string >::iterator l_it;;
  l_it=maplive.find(112);
  if(l_it==maplive.end())
  cout<<"we do not find 112"<<endl;
  else cout<<"wo find 112"<<endl;
  4,map中元素的删除:
  如果删除112;
  map<int ,string >::iterator l_it;;
  l_it=maplive.find(112);
  if(l_it==maplive.end())
  cout<<"we do not find 112"<<endl;
  else  maplive.erase(l_it);  //delete 112;
  5,map中 swap的用法:
  Map中的swap不是一个容器中的元素交换,而是两个容器交换;
  For example:
#include <map>
#include <iostream>
using namespace std;
int main( )
{
map <int, int> m1, m2, m3;
map <int, int>::iterator m1_Iter;
m1.insert ( pair <int, int>  ( 1, 10 ) );
m1.insert ( pair <int, int>  ( 2, 20 ) );
m1.insert ( pair <int, int>  ( 3, 30 ) );
m2.insert ( pair <int, int>  ( 10, 100 ) );
m2.insert ( pair <int, int>  ( 20, 200 ) );
m3.insert ( pair <int, int>  ( 30, 300 ) );
cout << "The original map m1 is:";
for ( m1_Iter = m1.begin( ); m1_Iter != m1.end( ); m1_Iter++ )
cout << " " << m1_Iter->second;
cout   << "." << endl;
// This is the member function version of swap
//m2 is said to be the argument map; m1 the target map
m1.swap( m2 );
cout << "After swapping with m2, map m1 is:";
for ( m1_Iter = m1.begin( ); m1_Iter != m1.end( ); m1_Iter++ )
cout << " " << m1_Iter -> second;
cout  << "." << endl;
cout << "After swapping with m2, map m2 is:";
for ( m1_Iter = m2.begin( ); m1_Iter != m2.end( ); m1_Iter++ )
cout << " " << m1_Iter -> second;
cout  << "." << endl;
// This is the specialized template version of swap
swap( m1, m3 );
cout << "After swapping with m3, map m1 is:";
for ( m1_Iter = m1.begin( ); m1_Iter != m1.end( ); m1_Iter++ )
cout << " " << m1_Iter -> second;
cout   << "." << endl;
}