使用 main 方法和 public static final int 计数到 2 个不同的值

Question

我目前运行遇到 "practice it" 问题，我被困在这个问题上： “假设您正在尝试编写一个使用循环产生以下输出的程序。下面的程序是对解决方案的尝试，但它至少包含四个主要错误。识别并修复它们。 1 3 5 7 9 11 13 15 17 19 21 1 3 5 7 9 11 “

public class BadNews {
    public static final int MAX_ODD = 21;

    public static void writeOdds() {
        // print each odd number
        for (int count = 1; count <= (MAX_ODD - 2); count++) {
            System.out.print(count + " ");
            count = count + 2;
        }

        // print the last odd number
        System.out.print(count + 2);
    }

    public static void main(String[] args) {
        // write all odds up to 21
        writeOdds();

        // now, write all odds up to 11
        MAX_ODD = 11;
        writeOdds();
    }
}

我已将代码更改为：

public class BadNews {
    public static final int MAX_ODD = 21;

    public static void writeOdds() {
        // print each odd number
        for (int count = 1; count <= (MAX_ODD); count++) {
            System.out.print(count + " ");
            count = count +1; //tried to chacge count++ into count + 2 but it was a miss
        }
    }

    public static void main(String[] args) {
        // write all odds up to 21
        writeOdds();

        // now, write all odds up to 11
        MAX_ODD = 11;
        writeOdds();
    }
}

我以为最后一个问题是 final int MAX_ODD 应该移到 main 中并更改为 "normal" 变量 (int MAX_ODD) 但它以问题失败和评论结束 "Your solution must have a class constant. A constant must be declared as 'public static final' outside of any methods in your class." 有什么解决办法吗？

Answer 1

此代码将为您提供预期的输出。

public static void main(String[] args) {
    writeOdds(21);
    writeOdds(11);
}

public static void writeOdds(int n) {
    // print each odd number
    for (int count = 1; count <= (n); count++) {
        System.out.print(count + " ");
        count = count +1; //tried to chacge count++ into count + 2 but it was a miss
    }
}

Answer 2

一个声明为final的属性在设置初始值后不能改变它的值。这个初始值是最终的。该变量必须保持在 class 级别，在任何方法之外，以便每个方法都可以访问它。因此，干脆把final这个词删掉。

使用 main 方法和 public static final int 计数到 2 个不同的值

counting to 2 different values with main method and public static final int

java

int

loops

final