C++中map用法（一）

C++中map用法

/************************************************************************

*

* Map的特点: 1、存储Key-value对

* 2、支持快速查找，查找的复杂度基本是Log(N)

* 3、快速插入，快速删除，快速修改记

*

/************************************************************************/

#include <iostream>

#include <string>

#include <map>

using namespace std;

 

 

int main()

{

map<const char*,int> m;

m["a"]=1;

m["b"]=6;

m["c"]=9;

map<const char*,int>::iterator it;

it=m.begin();

const char* c =it->first;

cout<<"first element is :"<<c<<endl;

int i = m["c"];

while(it!=m.end()){

cout << it->first<<";"<<it->second<<endl;

++it;

}

cout <<"m[\"c\"]="<<i<<endl;

cout <<"sizeof m:"<<m.size()<<endl;

cout <<"erase m[\"c\"](1:succ 0:failed):"<<m.erase("c")<<endl;

cout <<"erase m[\"c\"]:"<<m.erase("c")<<endl;

cout <<"sizeof m:"<<m.size()<<endl;

cout<<"m[c]="<<m["c"]<<endl;

cout<<"sizeof m :"<<m.size()<<endl;

 

return 0;

 

}

 

运行结果