c++map判断键值对是否存在

1.源码实现

#include <iostream>
#include <string>
#include <map>

using namespace std;

int main()
{
        map<int, string> mapStudent;
        map<int, string>::iterator it;

        mapStudent.insert(pair<int, string>(1, "student one"));
        mapStudent.insert(pair<int, string>(2, "student two"));
        mapStudent.insert(pair<int, string>(3, "student three"));

        it = mapStudent.find(2);

        if(it != mapStudent.end())
        {
                cout << "Find, the value is " << it->second << endl;
        }
        else
        {
                cout << "Do not find" << endl;
        }

        return 0;
}

2.编译源码

$ g++ -o example example.cpp

3.运行及其结果

$ ./example
Find, the value is student two