Python实现简单的四则运算

import random

from fractions import Fraction

operation = [‘+‘, ‘-‘, ‘*‘, ‘/‘]   #四则运算的符号

global f

def integer_score():

    #rand = operation[random.randint(0,3)]

    number = random.randint(1,4)     #随机产生的表达式长度

    f = ‘‘

    for i in range(number):

        a = random.randint(1,20)       #随机产生的表达式中的数

        rand = operation[random.randint(0, 3)]     #随机选择一个四则运算中的符号

        if rand == ‘/‘:

            b = random.randint(a, 20)               #随机产生的真分数的分母

            f += str(a) + rand + str(b)               #数与符号相连

            rand = operation[random.randint(0, 2)]     #随机选择一个四则运算中的符号

            f += rand

        else:

            f += str(a) + rand

        #print(a,rand,end=‘‘)

    b = random.randint(1, 20)

    f += str(b)                     #得到完整的表达式

    n = eval(f)                      #得到表达式的结果

    n = Fraction(‘{}‘.format(n)).limit_denominator()    #小数转化为分数

    if n > 0:

        print(‘题目：‘)

        print(f,‘=‘)

        print(‘请输出答案：‘)

        x = Fraction(‘{}‘.format(eval(input()))).limit_denominator()

        if n == x:                  #输入的数与表达式比较

            print(True)

        else:

            print(False)

            print(‘正确的答案为：‘,n)

    else:

        integer_score()

def integer():

    # rand = operation[random.randint(0,3)]

    number = random.randint(1, 3)

    f = ‘‘

    for i in range(number):

        a = random.randint(1, 10)

        rand = operation[random.randint(0, 3)]

        f += str(a) + rand

    b = random.randint(1, 10)

    f += str(b)

    n = eval(f)

    if isinstance(n, int) and n > 0:

        print(‘题目：‘)

        print(f, ‘=‘)

        print(‘请输出答案：‘)

        x = eval(input())

        if n == x:

            print(True)

        else:

            print(False)

            print(‘正确的答案为：‘, n)

    else:

        integer()

def score():

    op = [‘+‘, ‘-‘]

    number = random.randint(1, 3)

    f = ‘‘

    for i in range(number):

        a = random.randint(1, 10)

        b = random.randint(a, 10)

        rand = op[random.randint(0, 1)]

        f += str(a) + ‘/‘+ str(b)+rand

    a = random.randint(1, 10)

    b = random.randint(a, 10)

    f += str(a) + ‘/‘+ str(b)

    n = eval(f)

    n = Fraction(‘{}‘.format(n)).limit_denominator()

    if n > 0:

        print(‘题目：‘)

        print(f,‘=‘)

        print(‘请输出答案：‘)

        x = Fraction(‘{}‘.format(eval(input()))).limit_denominator()

        if n == x:

            print(True)

        else:

            print(False)

            print(‘正确的答案为：‘,n)

    else:

        score()



if __name__ == ‘__main__‘:

    while True:

        print(‘选择你想做的题目：‘)

        print(‘0(退出)1(分数题目)，2（整数题目),3(综合题目)‘)

        m = int(input())

        if m == 1:

            score()

        elif m == 2:

            integer()

        elif m == 3:

            integer_score()

        elif m == 0:

            exit()

        else:

            print(‘请重新输入你的选择‘)



#isinstance(1, int)