Algorithm help on converting infix expression to postfix
 

I found numerous examples on converting infix expression to postfix expression but my program needs to include some functions like sqrt(x), min/max(x,y), fact(x), abs(x). abs(-5) is converted to -5 abs 120 – (45+3) is converted to 120 45 3 + - (3^2 + 4^5)*fact(3) is converted to 3 2 ^ 4 5 ^ +...

To evaluate any arithmetic expression we convert the infix expression to postfix. Then evaluate the postfix expression using a stack.