java - 为什么这段代码使用随机字符串打印“hello world”？(Why does this code using random strings print “hello world”?)

Question

The following print statement would print "hello world".

(以下print语句将打印“hello world”。)

Could anyone explain this?

(有人能解释一下吗？)

System.out.println(randomString(-229985452) + " " + randomString(-147909649));

And randomString() looks like this:

(而randomString()看起来像这样：)

public static String randomString(int i)
{
    Random ran = new Random(i);
    StringBuilder sb = new StringBuilder();
    while (true)
    {
        int k = ran.nextInt(27);
        if (k == 0)
            break;

        sb.append((char)('`' + k));
    }

    return sb.toString();
}

  ask by 0x56794E translate from so

Answer 1

The other answers explain why, but here is how.

(其他答案解释了原因，但这里是如何。)

Given an instance of Random :

(给定一个Random实例：)

Random r = new Random(-229985452)

The first 6 numbers that r.nextInt(27) generates are:

(r.nextInt(27)生成的前6个数字是：)

8
5
12
12
15
0

and the first 6 numbers that r.nextInt(27) generates given Random r = new Random(-147909649) are:

(r.nextInt(27)生成给定的Random r = new Random(-147909649)的前6个数字是：)

23
15
18
12
4
0

Then just add those numbers to the integer representation of the character ` (which is 96):

(然后只需将这些数字添加到字符`的整数表示中（即96）：)

8  + 96 = 104 --> h
5  + 96 = 101 --> e
12 + 96 = 108 --> l
12 + 96 = 108 --> l
15 + 96 = 111 --> o

23 + 96 = 119 --> w
15 + 96 = 111 --> o
18 + 96 = 114 --> r
12 + 96 = 108 --> l
4  + 96 = 100 --> d