Language is C++

Please explain each step of code with comments

Integer Postfix Calculator Write a program that accepts a string that is a space-delimited integer arithmetic expression in postfix notation. Use a stack to compute the value. Example: The input string 54+310+ is equivalent to the infix expression (5+4)+(310) The answer is 39 . The algorithm is: Take the leftmost token from the string If it is numeric (which may include a unary operator), push that token onto the stack If it is a binary operation, pop the vector twice, apply the operation, and push the result When the input string is empty, the stack will contain one entry: the final answer Here's how the given string gets processed: The final answer, 39 , is the only element in the stack after all tokens in the string have been consumed. This problem has an extra twist. The string contains characters, so 10 isn't a ten, but is the char 1 followed by the char 0 . You will need to convert string representations of integers (signed and unsigned) into their integer values. You'll also need to handle unary - and +. We also have to worry about the three non-commuting operators /%. We will evaluate the postfix string 45 - as 4-5 and, likewise, will evaluate 45/ as 4/5 and 45% as 4%5. The program should continue to accept and process input strings until the user enters a zero as input. There's no need to check for validity; all input will be well-formed postfix expressions