"""
这是一个简单的计算器
"""
import re

operator = ('+', '-', '*', '/', '%', '^')


def calculate_two_numbers(num1, num2, op):
    if op == operator[0]:
        return num1 + num2
    if op == operator[1]:
        return num1 - num2
    if op == operator[2]:
        return num1 * num2
    if op == operator[3]:
        try:
            return num1 / num2
        except ZeroDivisionError:
            print("Error:division by zero")
            return False
    if op == operator[4]:
        try:
            return num1 % num2
        except ZeroDivisionError:
            print("Error:modulo by zero")
            return False
    if op == operator[5]:
        return num1 ** num2


def format_formula(formula):
    list_formula = [i for i in re.findall(r'\w*', formula)]
    list_formula += re.split(r'\w*',formula)
    list_formula_1 = []
    for item in list_formula:
        if item != '':
            list_formula_1.append(item)
    return list_formula_1


print("计算器支持两个正数的四则+-*/运算、模%运算、乘方^运算，请输入表达式开始或exit退出:")
while True:
    formula = input()
    if formula != 'exit':
        list1 = format_formula(formula)
        print(calculate_two_numbers(int(list1[0]), int(list1[1]), list1[2]))
    else:
        break