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Java 程序:使用递归来反转句子

原文: https://www.programiz.com/java-programming/examples/reverse-sentence

在此程序中,您将学习使用 Java 中的递归循环来反转给定的句子。

示例:使用递归反转句子

public class Reverse {

    public static void main(String[] args) {
        String sentence = "Go work";
        String reversed = reverse(sentence);
        System.out.println("The reversed sentence is: " + reversed);
    }

    public static String reverse(String sentence)
    {
        if (sentence.isEmpty())
            return sentence;

        return reverse(sentence.substring(1)) + sentence.charAt(0);
    }
}

运行该程序时,输出为:

The reversed sentence is: krow oG

在上面的程序中,我们有一个递归函数reverse()

在每次迭代中,我们使用charAt(0)将下一个reverse()函数的结果添加(连接)到句子的第一个字符。

递归调用必须在charAt()之前,因为这样最后一个字符将开始添加到左侧。 如果您颠倒顺序,您将得到原始句子。

最后,我们以空的sentencereverse()返回相反的句子结束。

执行步骤

迭代 reverse() substring() reversedString
1 reverse("Go work") "o Work" result + "G"
2 reverse("o Work") " Work" result + "o" + "G"
3 reverse(" Work") "Work" result + " " + "o" + "G"
4 reverse("Work") "ork" result + "W" + " " + "o" + "G"
5 reverse("ork") "rk" result + "o" + "W" + " " + "o" + "G"
6 reverse("rk") "k" result + "r" + "o" + "W" + " " + "o" + "G"
7 reverse("k") "" result + "k" + "r" + "o" + "W" + " " + "o" + "G"
最后 reverse("") - "" + "k" + "r" + "o" + "W" + " " + "o" + "G" = "kroW oG"