Question

我有这个显示某些错误的Java代码。我不明白这些错误。问题是“我必须一个人一个人的名字和收入，并将它们分别存储在各自的数组中，然后我必须在method（）中计算他们的所得税，并用他们的名字打印他们的所得税。”

import java.util.Scanner;

public class tax {
    int calculateTax(int Income) {

        int num, i;
        String[] arrayOfNames = new String[num];
        Long[] arrayOfIncome = new Long[num];

        int Incometax;
        if (Income >= 300000) {
            Incometax = (Income * 20) / 100;
            System.out.println(arrayOfNames[i] + ": " + Incometax);
        } else if (Income >= 100000 && Income <= 300000) {
            Incometax = (Income * 10) / 100;
            System.out.println(arrayOfNames[i] + ": " + Incometax);
        } else if (Income <= 100000) {
            System.out.println(arrayOfNames[i] + ": No tax" );
        }
        return Incometax;
    }

    public static void main(String[] args) {
        int num, i;
        String Name;
        int Income;


        System.out.println("Enter person count: ");
        Scanner scanner = new Scanner(System.in);
        num = scanner.nextInt();
        String[] arrayOfNames = new String[num];
        Long[] arrayOfIncome = new Long[num];


        for (i = 0; i < num; ++i) {

            System.out.println("Enter name " + (i + 1) + ":");
            arrayOfNames[i] = scanner.next();
            System.out.println("Enter " + arrayOfNames[i] + "'s income: ");
            arrayOfIncome[i] = scanner.nextLong();
            System.out.println();
        }
        for (i = 0; i <= num; i++) {
            int Incometax=calculateTax(int Income);
        }
        scanner.close();
    }
}

Answer 1

Op有很多错误：

从静态方法调用方法。
变量未初始化。
变量声明。
循环迭代。

所以我建议您学习一些基础知识并开始阅读有关Java的内容。

Answer 2

有些事情“错了”，有些事情可以做得更好。内联注释需要修复的内容（这不是固定的代码，只是指出您需要改进的地方）

import java.util.Scanner;

public class tax {
    /// typically, variables are camel cased (e.g. income instead of Income)
    int calculateTax(int Income) {

        int num, i;
        String[] arrayOfNames = new String[num];
        Long[] arrayOfIncome = new Long[num];

        /// As mentioned, variables should be camel case
        int Incometax;
        if (Income >= 300000) {
            Incometax = (Income * 20) / 100;
            /// At this point, arrayOfNames is empty, so this will error
            System.out.println(arrayOfNames[i] + ": " + Incometax);
        /// the <= 300000 is not needed here, as it will have triggered the first if
        } else if (Income >= 100000 && Income <= 300000) {
            Incometax = (Income * 10) / 100;
            /// At this point, arrayOfNames is empty, so this will error
            System.out.println(arrayOfNames[i] + ": " + Incometax);
        /// This can likely just be an else statement
        } else if (Income <= 100000) {
            /// At this point, arrayOfNames is empty, so this will error
            System.out.println(arrayOfNames[i] + ": No tax" );
        }
        return Incometax;
    }

    public static void main(String[] args) {
        int num, i;
        String Name;
        int Income;


        System.out.println("Enter person count: ");
        Scanner scanner = new Scanner(System.in);
        num = scanner.nextInt();
        String[] arrayOfNames = new String[num];
        Long[] arrayOfIncome = new Long[num];

            /// ++i increments before evaluation, so this will not work the way you
            /// think it will.  You will likely be one iteration "short"    
        for (i = 0; i < num; ++i) {
            /// i will be incremented before execution, so no need for i+1    
            System.out.println("Enter name " + (i + 1) + ":");
            arrayOfNames[i] = scanner.next();
            System.out.println("Enter " + arrayOfNames[i] + "'s income: ");
            arrayOfIncome[i] = scanner.nextLong();
            System.out.println();
        }
        /// You never use i within this for loop
        for (i = 0; i <= num; i++) {
            /// this will error, as you shouldn't have a type declaration in a method call
            /// Income has already been declared
            /// At this point, Income is 0, as it has not been assigned to.
            int Incometax=calculateTax(int Income);
        }
        scanner.close();
    }


}

Answer 3

int Incometax=calculateTax(int Income);

替换为

int Incometax=calculateTax(Income);

此外，calculateTax不是静态方法。因此，您不能从静态main调用它。

Answer 4

替换：

int Income;

具有：

int income;

只能将对象命名为大写。

和

calculateTax(int Income);

不正确，它不应包含类型。

calculateTax(Income); // is ok

Java显示缺少该类

4 个答案: