APL is a programming language in which arithmetic/mathematical expressions
are evaluated right to left
1+23 = 7 but 23+1 =8
4-2-1 = 3 (same as 4 - (2-1))
Portion enclosed in braces evaluated first as in (2*3)+1 which is 7.
Write a program in Java to evaluate APL expressions.
(Hint the expression is read as a string of characters and
pushed onto a stack and then pop operand2 and operator and operand1
then apply the operator to operand1 and operand2.