i'm new here.
i tried to execute this line:

while(getline(cin,in)){
..
..
}

and i've got an error message like this:

e554fb3f-1d51-4fef-96ef-f2a990bb5b2e(13): error: identifier "getline" is undefined
    while(getline(cin,in)){

but in my computer, i didn't get this error with my compiler. i read the FAQ carefully, but it can't help. how to solve this problem?