java - 计算子字符串，while循环

Question

public class SubstringCount
{
     public static void main(String[] args)
    { 
    Scanner scan = new Scanner(System.in);
    System.out.println("Enter a word longer than 4 characters, and press q to quit");
    int count = 0;


    while (scan.hasNextLine())
    {
        System.out.println("Enter a word longer than 4 characters, and press q to quit");
        String word = scan.next();

        if (word.substring(0,4).equals("Stir"))
        {
            count++;
            System.out.println("Enter a word longer than 4 characters, and press q to quit");
            scan.next();
        }

        else if (word.equals("q"))
        {
            System.out.println("You have " + count + ("words with 'Stir' in them"));
        }

        else if (!word.substring(0,4).equals("Stir")) 
        {
            System.out.println("Enter a word longer than 4 characters, and press q to quit");
            scan.next();
        }
    }
}

}

这里我需要打印用户输入的有多少个单词包含子字符串“Stir”。但是我不确定如何让它发挥作用，或者我是否一开始就做对了!

感谢您的帮助!

Answer 1

在您的代码中，以下行:输入长度超过 4 个字符的单词，然后按 q 退出 将在每次迭代中打印两次。另外，您使用了错误的函数来检查字符串是否包含子字符串。您的一些 if-else 语句需要更改。这是您的代码的更好版本:

import java.util.Scanner;

    public class SubstringCount
    {
         public static void main(String[] args)
         { 
             Scanner scan = new Scanner(System.in);
             System.out.println("Enter a word longer than 4 characters, and press q to quit");
             int count = 0;
             while (scan.hasNextLine())
             {
                String word = scan.next();
                if (word.contains("Stir"))
                {
                  System.out.println("Enter a word longer than 4 characters, and press q to quit");
                  count++;
                }
                else if (word.equals("q"))
                {
                  System.out.println("You have " + count + ( "words with 'Stir' in them"));
                  System.out.println("Enter a word longer than 4 characters, and press q to quit");
                }   
                else
                {
                  System.out.println("Enter a word longer than 4 characters, and press q to quit");
                }
             } //end of while
        }      //end of main
    }          //end of class

请注意，在这种情况下，您陷入了无限 while 循环。为了在输入q时真正“退出”，您应该break并从while中退出。