Question

When try to run below piece of code,It compiles without any errors.

int main()
{
    queue<map<int,int> >run_time;
}

But,now when I try to push something into the queue using the below code.

int main()
{
    queue<map<int,int> >run_time;

    run_time.push(make_pair(1,2));
    run_time.push(make_pair(3,4));
}

I get error as :

no matching function for call to 'std::queue<std::map<int,int,std::less<int>,std::allocator<std::pair<const int,int>

Answer 1

The problem is that make_pair doesn’t create a map. You’ll need to create the map beforehand, insert into it with make_pair, and insert the map itself into the queue.

map<int,int> x;
x.insert(make_pair(1,2));
run_time.push(x);