misc/utils/rpn.py at be926d3ed018b1fde8ae62b95ba875a17af11c45 · daedalus/misc · GitHub

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#!/usr/bin/env python
# A simple reverse polish notation calculator
# Author Dario Clavijo 2018

r = 0
a = 0
b = 0

stack = []
while True:
    ops = str(input(">"))
    if ops != "":
        ops = ops.split()
        for op in ops:
            stack.append(op)
            if op == "*":
                a = int(stack[-2])
                b = int(stack[-3])
                r = a * b
                stack.pop()
                stack.pop()
                stack.pop()
                stack.append(r)
                print(r)
            elif op == "+":
                a = int(stack[-2])
                b = int(stack[-3])
                r = a + b
                stack.pop()
                stack.pop()
                stack.pop()
                stack.append(r)
                print(r)
            elif op == "-":
                a = int(stack[-2])
                b = int(stack[-3])
                stack.pop()
                stack.pop()
                stack.pop()
                r = a - b
                stack.append(r)
                print(r)
            elif op == "/":
                a = int(stack[-2])
                b = int(stack[-3])
                stack.pop()
                stack.pop()
                stack.pop()
                r = a / b
                stack.append(r)
                print(r)
        print(stack)