2016-03-17 70 views
-1

我即將完成此程序,但它無法運行,因爲它需要一個主要方法。然而,無論何時我輸入它,我都會收到錯誤代碼表達式的非法開始。有人可以指出這個代碼片段中主要方法的屬性嗎?貝婁是我寫的代碼。我也被指示使用Javadoc實用程序工具,但我仍然不確定它是什麼以及如何使用它。我相信,我在正確的軌道上,通過使用java.util.doc主要方法DriverMortgageClass.java

import javax.swing.*; 
 
import java.text.*; 
 
import java.util.*; 
 

 
public class DriverMortgageClass 
 
{ 
 

 

 
    public double annualInterestRate; 
 
    public int numberOfYears; 
 
    public double loanAmount; 
 
    public double monthlyPayment; 
 
    public double totalPayment; 
 

 
    
 
    //set decimal format 
 
    DecimalFormat df= new DecimalFormat ("0.00"); 
 
    
 
    private Mortgage mortgage; 
 
    
 
    public DriverMortgageClass() 
 
    { 
 
    
 
    mortgage = new Mortgage(); 
 
    } 
 

 
public void start() 
 
{ 
 
    
 
//get input for interest rate 
 
String annualInterestRateString = JOptionPane.showInputDialog(null,"Enter yearly interest rate, for example 8.25",JOptionPane.QUESTION_MESSAGE); 
 
annualInterestRate=Double.parseDouble(annualInterestRateString); 
 
mortgage.setAnnualInterestRate(annualInterestRate); 
 

 
//get input for number of years 
 
String numberOfYearsString = JOptionPane.showInputDialog(null,"Enter number of years as an integer, for example 5",JOptionPane.QUESTION_MESSAGE); 
 
numberOfYears= Integer.parseInt(numberOfYearsString); 
 
mortgage.setNumberOfYears(numberOfYears); 
 

 
//set loan amount 
 
String loanAmountString = JOptionPane.showInputDialog(null,"Enter loan amount, for example 120000.95",JOptionPane.QUESTION_MESSAGE); 
 
loanAmount= Integer.parseInt(loanAmountString); 
 
mortgage.setLoanAmount(loanAmount); 
 

 

 
//calculate the monthly and total payment 
 
monthlyPayment=loanAmount*annualInterestRate /(1-(Math.pow(1/(1+annualInterestRate),numberOfYears*12))); 
 
totalPayment=monthlyPayment*numberOfYears*12; 
 

 
//display monthly and total payment 
 
JOptionPane.showMessageDialog(null,"The monthly payment is"+monthlyPayment 
 
+"The total payment is"+totalPayment); 
 
     
 

 
System.exit(0); 
 
}// end main method 
 
}

+0

我也有另一個程序,與這封裝信息沒有包含在這個文件中。如果需要,我可以提供,但我真的需要知道的是在哪裏輸入我的主要方法的正確位置,以便我的程序能夠運行。 – David

+3

主要方法必須具有簽名'public static void main(String [])''。你沒有這樣的方法。因此,你沒有一個主要的方法。 – bcsb1001

回答

3

它需要一個main方法

然後添加一個主要方法和JavaDoc的

/** 
* This is a JavaDoc. Describe the class here. 
* 
**/ 
public class DriverMortgageClass 
{ 


    // Other code... 

    public static void main(String[] args) { 
     new DriverMortgageClass().start(); 
    } 
}