Question

现在，我正在进行一项练习，要求我使用几种不同的方法，并在main方法中调用所有这些方法。该代码专门要求用户提交申请状态和年收入，以便用他们自己的单独方法计算用户的扣除金额，税率，应税收入和税额。然后在main方法中，我需要调用这些方法并根据用户输入的内容打印出它们返回的值。这就是我到目前为止所做的：

import java.util.*;

public class TaxActivity{
 public static double getDeductionAmount(double filingStatus){
    Scanner sc = new Scanner(System.in);
    int deductionAmount;
    if (filingStatus==1){
        deductionAmount=6350;
    }else if(filingStatus==2){
        deductionAmount=12700;
    }else{
        deductionAmount=9350;
    }
    return deductionAmount; 
 }
 public static double getTaxBracket(double filingStatus, double yearlyIncome){
    Scanner sc = new Scanner(System.in);
    double taxRate;
    if (filingStatus==1){
        if (yearlyIncome>=0&&yearlyIncome<9325){
        taxRate=10.0;
        }else if(yearlyIncome>=9325&&yearlyIncome<37950){
        taxRate=15.0;
        }else if(yearlyIncome>=37950&&yearlyIncome<91900){
        taxRate=25.0;
        }else if(yearlyIncome>=91900&&yearlyIncome<191650){
        taxRate=28.0;
        }else if(yearlyIncome>=191650&&yearlyIncome<416700){
        taxRate=33.0;
        }else if(yearlyIncome>=416700&&yearlyIncome<418400){
        taxRate=35.0;
        }else{
        taxRate=39.6;
        }
    }else if(filingStatus==2){
        if (yearlyIncome>=0&&yearlyIncome<18650){
        taxRate=10.0;
        }else if(yearlyIncome>=18650&&yearlyIncome<75900){
        taxRate=15.0;
        }else if(yearlyIncome>=75900&&yearlyIncome<153100){
        taxRate=25.0;
        }else if(yearlyIncome>=153100&&yearlyIncome<233350){
        taxRate=28.0;
        }else if(yearlyIncome>=233350&&yearlyIncome<416700){
        taxRate=33.0;
        }else if(yearlyIncome>=416700&&yearlyIncome<470700){
        taxRate=35.0;
        }else{
        taxRate=39.6;
        }
    }else{
        if (yearlyIncome>=0&&yearlyIncome<13350){
        taxRate=10.0;
        }else if(yearlyIncome>=13350&&yearlyIncome<50800){
        taxRate=15.0;
        }else if(yearlyIncome>=50800&&yearlyIncome<131200){
        taxRate=25.0;
        }else if(yearlyIncome>=131200&&yearlyIncome<212500){
        taxRate=28.0;
        }else if(yearlyIncome>=212500&&yearlyIncome<416700){
        taxRate=33.0;
        }else if(yearlyIncome>=416700&&yearlyIncome<444550){
        taxRate=35.0;
        }else{
        taxRate=39.6;
        }
    }
    return taxRate;
 }
 public static double getTaxableIncome(double deductionAmount, double yearlyIncome){
    Scanner sc = new Scanner(System.in);
    double taxableIncome= yearlyIncome - deductionAmount;
    return taxableIncome;
 }
 public static double getTaxAmount(double taxableIncome, double taxRate){
        double taxAmount=(double)taxableIncome*taxRate;
        return taxAmount;
 }
 public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    System.out.println("Enter your filing status: ");
    System.out.println("1. Single ");
    System.out.println("2. Married Filing Jointly ");
    System.out.println("3. Head of Household ");
    System.out.println("");
    System.out.print("Enter either 1, 2, or 3: ");
    double filingStatus = sc.nextDouble();
    System.out.println("");

    System.out.println("Enter your yearly income: ");
    double yearlyIncome = sc.nextDouble();
    System.out.println("");

    System.out.println("Your Deduction Amount is: $"+getDeductionAmount(filingStatus));
    System.out.println("Your Tax Rate is: "+getTaxBracket(filingStatus,yearlyIncome)+"%");
    System.out.println("Your Taxable Amount is: $"+getTaxableIncome(deductionAmount,yearlyIncome));
    System.out.println("Your Amount of Tax Due is: $"+getTaxAmount(taxableIncome,taxRate));
 }
}

但是，当我运行代码时，我会收到这些错误：

TaxActivity.java:96: error: cannot find symbol
            System.out.println("Your Taxable Amount is: $"+getTaxableIncome(deductionAmount,yearlyIncome));

symbol:   variable deductionAmount
location: class TaxActivity



TaxActivity.java:97: error: cannot find symbol
            System.out.println("Your Amount of Tax Due is: $"+getTaxAmount(taxableIncome,taxRate));

symbol:   variable taxableIncome
location: class TaxActivity



TaxActivity.java:97: error: cannot find symbol
System.out.println("Your Amount of Tax Due is: $"+getTaxAmount(taxableIncome,taxRate));

symbol:   variable taxRate
location: class TaxActivity
3 errors

我仍然从Java开始，所以调用方法对我来说仍然是一个新概念，但我似乎无法看到可能导致这些错误的原因。我确保使所有变量都是相同的类型，并为所有方法使用正确的参数。我能想到的唯一可能导致问题的是代码的格式错误，我无法注意到。如果你们中的任何一个人能够指出导致这个错误的原因，我会很感激。

Answer 1

您无法在另一个方法中创建的一个方法中访问变量。

您的主要方法有：

deductionAmount

但主方法中没有变量int deductionAmount = getDeductionAmount(filingStatus);。您确实运行了计算它的函数，但您从未将它保存到main方法中的变量中。你应该做的：

taxableIncome

与http://类似。

Answer 2

您应该在{main}方法中存储getDeductionAmount(filingStatus)方法的返回值就像浮动deductionAmount = getDeductionAmount(filingStatus)一样，你必须将你的扣减金额传递给getTaxableIncome(deductionAmount,yearlyIncome)方法。

同样，您应该存储应税收入和taxRate。
然后用打印和传递给其他方法的变量做你想做的事。

关于如何在main方法中调用多个方法所需的建议

2 个答案: