条件语句，while循环语句：完整的温度转换程序

while True:
    a = int(input('摄氏转华氏请按 1\n华氏转摄氏请按 2\n退出请按3\n'))
    if a==1:

        c = float(input('请输入摄氏度:'))

        f = c*9/5+32

        print('摄氏{:.2f}的华氏为{:.2f}\n'.format(c,f))

    elif a ==2:

        f  = float(input('请输入华氏温度:'))

        c = 5/9*(f-32)

        print('华氏{:.2f}的摄氏为{:.2f}\n'.format(c,f))

    else:
        break