#include<stdio.h>
#include<map>
using namespace std;
 
int main() {
	/*
	map.find(key)返回键为key的映射的迭代器
	*/
	map<char, int> mp;
	mp['m'] = 20;
	mp['r'] = 30;
	mp['a'] = 40;
	map<char, int>::iterator it = mp.find('a');
	if (it !=mp.end()){
		printf("%c %d\n", it->first,it->second); // 只有map迭代器可以使用first/second方式
	}
	else {
		printf("没找到\n");
	}
 
 
 
	return 0;
}

https://blog.csdn.net/jinghuashuiyuedi/article/details/54347844