Question

我正在编写一个简单的程序，将歌词写在墙上的99瓶啤酒上。但是，当我在while循环内调用该函数时，我编写的从bottleNum中减去一个的函数不起作用。我不确定我在这里做了什么？我不应该能够在while循环内调用函数吗？运行代码时没有出现错误，一遍又一遍地打印文本，并且bottleNum始终等于99。

#pragma comment(lib, "MyLib.lib")

Answer 1

如果您这样做，它将起作用：

bottlesNum = 99

def bottle_subtraction(bottles):
    bottles = bottles - 1
    return bottles # we return the updated value here

while bottlesNum > 0:
    if bottlesNum != 1:
        print("{x} bottles of beer on the wall, {x} bottles of beer".format(x = bottlesNum))
    elif bottlesNum == 1:
        print("{x} bottle of beer on the wall, {x} bottle of beer".format(x = bottlesNum))

    bottlesNum = bottle_subtraction(bottlesNum) # we store the updated variable

    print("Take one down and pass it around, {} bottles of beer on the wall".format(bottlesNum))

Answer 2

这应该有效：

bottlesNum = 99

def bottle_subtraction(bottles):
    bottles = bottles - 1
    return bottles

while bottlesNum > 0:
    if bottlesNum != 1:
        print("{x} bottles of beer on the wall, {x} bottles of beer".format(x = bottlesNum))
    elif bottlesNum == 1:
        print("{x} bottle of beer on the wall, {x} bottle of beer".format(x = bottlesNum))

    bottlesNum = bottle_subtraction(bottlesNum)

    print("Take one down and pass it around, {} bottles of beer on the wall".format(bottlesNum))

之所以不起作用，是因为调用该函数时，您没有返回任何值，而您所做的只是提供了一个引用。

在while循环内无法调用函数

2 个答案: