A postfix calculator takes its input in postfixnotation . You may be familiar wi

Question

A postfix calculator takes its input in postfixnotation. You may be familiar with infix notation, where theoperator is placed between the operands. (e.g. 1 * 2 + 3). Postfixnotation places the operators after the operands (e.g. 1 2 * 3 +).Postfix notation removes the need for parentheses and operatorpriorities, which are necessary for infix notation. A postfixcalculator records numbers entered in a stack. An operator takesthe top two elements from the stack, applies the operation andpushes the result back to the stack.

Your program takes its input (postfix expressions) from stdinand returns the result of the calculation (the last number left onthe stack) to stdout.

Input consists of a string of numbers and operators separated bysome amount of whitespace. There will be no more than 50 operatorsin this string. Read until EOF.

Output the decimal 32-bit signed integer result of thecalculation, followed by a newline. You do not need to handle anyinteger overflow or division by 0 at any point during the executionof your program.

Explanation / Answer

1. Make a stack int stack[200]; 2. Scan in using fscanf(stdin, "%s", input); 3. Check if it is a number using if(isdigit(input[0] If it is then...convert it into a digit using atoi since inputis a string, then push it to the stack: stack[0] = atoi(...); If it is not a digit, it would be +, -, /, or *, so you shouldhave 4 more ifs to check these... say if your input is 2 3 5 + + then the stack will have |2|3|5| , stack[0] =2, stack[1] = 3,stack[2] = 5 4. If it is a '+' then you should add stack[2] with stack[1],then push the result to stack[1]. It's a good idea to have a "top"variable to keep track of the top. For the other operators it's similar. Good luck :)

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