How to read only what comes after the comma from txt file

[aliciabilbao]

I have a file that has several presidents' names and their party affiliation, like so;

George Washington,Unaffiliated
John Adams,Federalist
Thomas Jefferson,Democratic-Republican
James Madison,Democratic-Republican
James Monroe,Democratic-Republican

I have to store ONLY the party affiliation into a vector. How do I put a delimiter that stores only what comes after the comma?

[lastchance]

#include <iostream>
#include <string>
#include <sstream>
#include <fstream>
#include <vector>
using namespace std;

int main()
{
// ifstream in( "data.txt" );
   istringstream in( "George Washington,Unaffiliated\n"
                     "John Adams,Federalist\n"
                     "Thomas Jefferson,Democratic-Republican\n"
                     "James Madison,Democratic-Republican\n"
                     "James Monroe,Democratic-Republican\n"     );


   vector<string> affiliation;
   for ( string president, party; getline( in, president, ',' ) && getline( in, party ); ) affiliation.push_back( party );

   for ( string s : affiliation ) cout << s << '\n';
}

Unaffiliated
Federalist
Democratic-Republican
Democratic-Republican
Democratic-Republican

[aliciabilbao]

Thank you!