blue, please
review this tutorial and even
this example. Use Google until you're satisfied you've discovered your understanding. Simply put, casting is the forcing of one type to another.
And for your problem.. in that situation you want to cast the computation in computeAverage() to a
double. However, not to confuse you, but this will not work as trying to cast an int - which has already been truncated, will not produce your desired effect. Instead, you might want to change every int you already have into a double(static double a = 53; ). From there, you can down-cast to an int if you need it. Is there a reason you're using int's specifically? You can't up-cast from an int to a double and expect precision.... something to consider.