Reverse-Polish-Notation (RPN) is a machine friendly form of calculating expressions. Example, to evaluate, (1+2)*4 + 5 - 3 you enter the sequence into the calculator as, '5 1 2 + 4 * + 3 -' and obtain the result.

For this challenge write a RPN calculator for simple arithmetic expressions, '+','-','*','%','/'

Note: Chosen interpretations of operators, illustrated from first few test cases, are as follows: rpn('a','b','-') is interpreted as 'a-b', while rpn('a','b','/') is interpreted as 'b/a'. and rpz('a','b','%') which is interpreted as 'b%a'.

with operator '%' 'b % a' being mod(b,a) operator.

Following your 'stack' solution to http://www.mathworks.com/matlabcentral/cody/problems/1303-is-the-paranthesis-sequence-balanced try using a expression, and a value stack to work this problem.

Hint: http://en.wikipedia.org/wiki/Reverse_Polish_notation