java - 错误java。我不知道如何修复它

Question

我正在学习 java，这段代码有一个错误。我根本不知道如何解决它。

代码如下:

public class CountLettersInArray {

    public static void main(String[] args) {
    char[] chars = createArray();

    System.out.println("The lowercase letters are:");
    displayArray(chars);    

    int[] counts = countLetters(chars);

    System.out.println(" ");
    System.out.println("The occurence of each letter are: ");
    displayCounts(counts);
    }

    public static void displayCounts(int[] counts) {
        for (int i = 0; i < counts.length; i++);
            if ((i + 1) % 10 == 0);
                System.out.println(counts[i] + " " + (char)(i + 'a'));
                else 
                    System.out.println(counts[i] + " " + (char)(i + 'a') + " ");


    }

    public static int[] countLetters(char[] chars) {
        //Declare and create an array of 26 int
        int[] counts = new int[26];

        //For each lowercase letter in the array, count it
        for (int i = 0; i < chars.length; i++);
            counts[chars[i] - 'a']++;

        return counts;
    }

    public static void displayArray(char[] chars) {
        //Display the characters in the array 20/line
        for (int i = 0; i < chars.length; i++);
            if ((i + 1) % 20 == 0)
                System.out.println(chars[i]);
            else
                System.out.print(chars[i] + " ");
    }

    public static char[] createArray() {
        //Declare the array of characters and create it
        char[] chars = new char[100];

        //Create lowercase characters randomly and assign them to array
        for (int i = 0; i < chars.length; i++);
            chars[i] = RamdomCharacter.getRandomLowerCaseLetter();
        //This return the array 
        return chars;
    }

}

我正在使用 Eclypse 进行编码，软件告诉我这两件事:

Exception in thread "main" java.lang.Error: Unresolved compilation problems: 
    i cannot be resolved to a variable
    RamdomCharacter cannot be resolved

我该如何解决这个问题？

Answer 1

您将 ; 放在循环的末尾:

for (int i = 0; i < counts.length; i++);
                                       ^

去掉这些，并用 {} 包围循环体。

现在的问题是 i 仅存在于循环范围内。但是，您已通过添加 ; 终止了循环范围，因此当您在外部引用 i 时，您会收到编译错误。