In your Student Class

the calculation

Code:
Gpa = cHours/pEarned;
is double = int/int

now the int/int will return an int value (in your case cHours is less than pEarned so the result is 0.something, but the something is being trimmed off since it is an int)

to prevent this you must first cast the variables to double and then divide, this can be done as follows

Code:
Gpa = (double)(cHours)/(double)(pEarned);