Question

我是第一个计算机科学课的学生。我试图找出如何设置变量，以便它需要一个数字附加到我们的老师设置的命令./integerProperties。请查看我编写的代码，我可以在如何获取输入时使用一些帮助，并将其插入我的名为number的变量中。

27 │Example output for:  ./integerProperties 1983
28 │
29 │    The number is even:
30 │    false
31 │    The number is odd:
32 │    true
33 │    The number is evenly divisible by three:
34 │    true
35 │    The number is evenly divisible by five:
36 │    false
37 │    The number is evenly divisible by seven:
38 │    false
39 │    How many groups of ten?
40 │    198
41 │    How many groups of hundred?
42 │    19
43 │    The additive inverse:
44 │    -1983
45 │
46 │
47 │
48 │    */
49 │ let firstParameter = CommandLine.arguments[1]
50 │ var number: Int
51 │
52 │ print("The number is even:")
53 │ print(number % 2 == 0)
54 │ print("The number is odd ")
55 │ print(number % 2 != 0)
56 │ print("the number is evenly divisible by 3")
57 │ print(number % 3 == 0)
58 │ print("the number is evenly divisible by 5")
59 │ print(number % 5 == 0)
60 │ print("the number of evenly divisible by 7")
61 │ print(number % 7 == 0)
62 │ print("how many groups of ten")
63 │ print(number / 10)
64 │ print("how many groups of hundreds")
65 │ print(number / 100)
66 │ print("the additive inverse")
67 │ print(number * -1)

Answer 1

使用Int(String)将参数解析为整数。请注意，如果字符串不是整数，它将返回nil Int?，您应该处理这种情况。

guard let number = Int(firstParameter) else {
    fatalError("firstParameter is not an Int")
}

编辑：您还应该检查参数是否存在，否则CommandLine.arguments[1]将失败，索引超出范围。

在Swift中协助变量

1 个答案: