输出文件中最长和最短的文本，并发现回文不起作用？

您可以查看下面的代码，所以对你的问题的第一部分“空白/没有为最短”你需要从文件中获得的第一个字符串和它的长度分配到两个max和min变量在你的代码，并随后得到了下一个字符串while循环中的文件，无论如何你已经在做。在代码中的问题是你min一直都是，0而你if(len<min)永远都不是真实的，这就是为什么每次都会得到最短的字符串为空的原因。

对于问题的第二部分，*如何/在何处将这段代码合并到我的代码（即回文代码）中，您可以创建一个单独的方法，findPalindrome()并在找到最短代码后从现有代码中调用此方法。和文件中最长的字符串。

public class Practice {

    public static void main(String args[])throws IOException {
        Scanner sc = new Scanner(new File("c:/code/names.txt"));
        String city="", longest="", shortest="";
        int len=0, min = 0, max = 0;

        if(sc.hasNext()) {
             city= sc.nextLine();
             len= city.length();
             min = len;
             max=len;
             longest=city;
             shortest=city;
        }

        while(sc.hasNext()) {
            city= sc.nextLine();
            len= city.length();
            if(len>max)
            {
                max=len;
                longest=city;
            }
            if(len<min)
            {
                min=len;
                shortest=city;
            }
        }
        System.out.println(longest + " is the longest name.");
        System.out.println(shortest + " is the shortest name.");
        findPalindrome();
    }


    public static void findPalindrome() throws FileNotFoundException {
        String s="";
        Scanner sc= new Scanner(new File("c:/code/names.txt"));
        while(sc.hasNextLine()) {
            String word = sc.nextLine();

            for(int i = word.length() - 1; i >= 0; i--){
                s = s + word.charAt(i);
            }

            if (word.equalsIgnoreCase(s)){
                System.out.println(word + " is a palindrome");
            }
            s="";
        }
        sc.close();
    }
}

输出：

Massachusetts is the longest name.
Ohio is the shortest name.
Kinikinik is a palindrome
Glenelg is a palindrome

如果您不想两次读取文件，则可以使用以下代码

public static void main(String args[])throws IOException {
    Scanner sc = new Scanner(new File("c:/code/names.txt"));
    String city="", longest="", shortest="";
    int len=0, min = 0, max = 0;
    String palindromeStr = "";
    if(sc.hasNext()) {
         city= sc.nextLine();
         len= city.length();
         min = len;
         max=len;
         longest=city;
         shortest=city;
         palindromeStr = findPalindrome(city);
    }

    while(sc.hasNext()) {
        city= sc.nextLine();
        len= city.length();
        if(len>max)
        {
            max=len;
            longest=city;
        }
        if(len<min)
        {
            min=len;
            shortest=city;
        }
        palindromeStr += findPalindrome(city);
    }
    System.out.println(longest + " is the longest name.");
    System.out.println(shortest + " is the shortest name.");
    System.out.println(palindromeStr);
}


public static String findPalindrome(String word) throws FileNotFoundException {
    String s="";
    for(int i = word.length() - 1; i >= 0; i--){
        s = s + word.charAt(i);
    }
    if (word.equalsIgnoreCase(s)){
       return word + " is a palindrome\n";
    }
    s="";
    return "";
}

输出：

Massachusetts is the longest name.
Ohio is the shortest name.
Kinikinik is a palindrome
Glenelg is a palindrome

回答来源：Stack Overflow