Proper use of a for loop
I am taking a c++ class right now and I know that a for loop will work like this but I was wondering if it was "normal" or "proper"

    for (int i = 0; getline(cin, input); i++)
Should this instead be

    int i = 0;
    while (getline(cin, input))
        i++;
I'm just wondering because I know a for loop is supposed to be a counter loop but the condition for this one does not have to do with an amount of times going through that i controls.
Proper use of a for loop
===

I am taking a c++ class right now and I know that a for loop will work like this but I was wondering if it was "normal" or "proper"

    for (int i = 0; getline(cin, input); i++)
Should this instead be

    int i = 0;
    while (getline(cin, input))
        i++;
I'm just wondering because I know a for loop is supposed to be a counter loop but the condition for this one does not have to do with an amount of times going through that i controls.