使用pair< int，int>作为地图的关键 [英] Using pair<int, int> as key for map

问题描述

根据上一个问题，我正在尝试创建地图使用一对整数作为关键字 map< pair< int，int> int> ，我找到了如何插入信息：

Based on a previous question, I am trying to create a map using a pair of integers as a key i.e. map<pair<int, int>, int> and I've found information on how to insert:

#include <iostream>
#include <map>

using namespace std;

int main ()
{
map<pair<int, int>, int> mymap;

mymap.insert(make_pair(make_pair(1,2), 3)); //edited
}   

但我似乎无法访问元素！我试过 cout<< mymap [（1,2）]< endl; 但它显示一个错误，我找不到如何使用键访问元素的信息。

but I can't seem to access the element! I've tried cout << mymap[(1,2)] << endl; but it shows an error, and I can't find information on how to access the element using the key. Am I doing something wrong?

推荐答案

您需要一个键作为键 cout< mymap [make_pair（1,2）]< endl; 您目前拥有的 cout<< mymap [（1,2）]< endl; 不是正确的语法。

you need a pair as a key cout << mymap[make_pair(1,2)] << endl; What you currently have cout << mymap[(1,2)] << endl; is not the correct syntax.

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