输入计数，谨防isdigit和int的坑

Posted 2021-01-10 chenxiaokaikai

total = 0
# 因为下面有isdigit判断，所以把num看成str类型，固后面的num需要独立int，若在total上一行int(num)则不生效
while 1:
    num = input("请输入0-999中的数，输入-1结束：")
    if num == "-1":
        break
    elif num.isdigit() and 0 <= int(num) < 1000:
        total += 1
        print("您已有效输入%d次"%total)
    else:
        print("输入有误，请重新输入！")