c++ STL map常见用法

#include<iostream>
#include<string>
#include<map>
using namespace std;
int main(){
	
	//定义 
	map<int, string> map1;
	
	//插入直接和数组一样就行哈哈
	map1[1] = "Hello";
	map1[2] = "World";
	int a = 3;string s = "!";
	map1[a] = s;  
	cout << map1[1] << " " << map1[2] << map1[3] << endl; 
	
	//根据key判断元素是否存在 
	cout << map1.count(3) << endl;
	
	//根据key查找元素 
	map<int, string> :: iterator it;
	it = map1.find(3);
	cout << it->first << " " << it->second << endl; 
	
	//删除key为3的元素 
	map1.erase(3);
	cout << map1.count(3) << endl;
	
	//遍历 
	for(it = map1.begin(); it != map1.end(); it++){
		cout << it->first << " " << it->second << endl;
	} 
	return 0;
}