an extra value being printed? how to get rid of it?

i am reading from .csv file and then mapping the data into a map. but an extra value is being printer again and again. how do i get rid of it?

while ( istream! = 0) {

string a;

getline (istream , a , ',' );//delimiting

int num = 0;

istream >> num;

cout << a << " ";

cout << num << endl ;// extra 0 being printed here

input[a] = num ;// values being stored in a map

}