doing testing on the function. I think is that is there any ways for the data types to store both the character or integers instead of using int for integers only and char for character only. This is my biggest problem.Because my function store only 2 int with a operator sign, what should I do if I had 2 operators, 3 operands, Then 3 operators, 4 operands, not possible to store all in so many functions. Seriously this is very difficult.