How to print a string with values in it?

Question

I am trying to print out the address value that I stored in the string. After I compile, it shows error: no match for 'operator<<'. Does that mean what inside the Address_list is not matched something?

#include <iostream>
#include <string>
#include <map>
#include "IPHost.h"

using namespace std;

int main() {
    map<string, IPHost> Address_list;
    Address_list["google.com"]=IPHost(74,125,225,20);
    cout << "google.com has address" << Address_list["google.com"] << endl; 
}

does IPHost have operator<< overloaded? – user2970916 Dec 11 '14 at 16:56 — user2970916, Dec 11 '14 at 16:56
Or does it have some kind of "to string" functionality? – crashmstr Dec 11 '14 at 16:57 — crashmstr, Dec 11 '14 at 16:57
@jww That is really helpful, thank you very much. – GublacK Dec 11 '14 at 17:21 — GublacK, Dec 11 '14 at 17:21

score 3 · Accepted Answer · answered Dec 11 '14 at 16:58

3

Address_list["google.com"]

would return instance of IPHost class which you stored earlier. And then it would try to apply operator<< to that instance for which it's emitting error.

This means you have not overloaded operator<< for your IPHost class.

answered Dec 11 '14 at 16:58

ravi

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score 1 · Answer 2 · answered Dec 11 '14 at 17:12

As mentioned by others you need an overloaded operator<< for IPHost...

...which you would do like this:

inline std::ostream& operator<<(std::ostream& os, const IPHost& host)
{
   // code to stream the contents of IPHost out to os here
   // for example:
   os << "IPHost{" << host.address() << "}";

   // remember to return a reference to the ostream
   return os;
}

How to print a string with values in it?

2 Answers2