C ++-通过引用模板函数传递STL映射

Question

What is wrong in this code as I am getting segmentation fault It seems returning map by value is not problematic.

#include<bits/stdc++.h>
using namespace std;

template<typename T>
T myMapIntersect(T& left, T& right)
{ }

int main()
{
    map<string, int> m;
    m["aa"] = 1;
    m["bb"] = 1;
    m["vf"] = 1;
    m["hh"] = 1;

    myMapIntersect< map<string,int> >(m, m);
    return 0;
}

Answer 1

You need to return in your function

#include<bits/stdc++.h>
using namespace std;

template<typename T>
T myMapIntersect(T& left, T& right)
{
    return left;
}

int main()
{
    map<string, int> m;
    m["aa"] = 1;
    m["bb"] = 1;
    m["vf"] = 1;
    m["hh"] = 1;

    myMapIntersect< map<string,int> >(m, m);
    return 0;
}