Question

Is there a very simple algorithm to figure out which of 4 numbers is the greatest?

Answer 1

If you’re using a language that supports some sort of max function or array sorting definitely use those features. Or choose any of the other sane answers in this thread. However, just for fun:

maximum = (var1 > var2 ? var1 : var2) > (var3 > var 4 ? var3 : var 4) ? 
             (var1 > var2 ? var1 : var2) : 
             (var3 > var 4 ? var3 : var 4);