I need to create a program that uses a stack to evaluate postfix arithmetic expressions (use only 4 arithmetical operators: +, -, *, /).
The numbers can only be single-digit intergers. The numbers and operators are separated by single spaces. I have to use the function isdigit() to check whether a character is a digit, and the function atof() to convert a string to a float number. I was wondering if anyone can give me any tips or something. Stacks are new to me so it's hard for me to understand how these work. Also, I have no idea why she wants the atof() function. It doesn't seem to serve any purpose to me in the program, but that may be because I'm not seeing the full purpose of the program and that I've never used that function. Please help.