Solved

Problem with loop initialization

Posted on 2004-09-14
6
243 Views
Last Modified: 2010-03-31
I am almost finished with my Java homework, the 'classic' mortgage amortization.  It runs fairly well except I can't figure out how to stop the first month from displaying all zeros.  It should be starting with the data displayed in week 2...

What am I doing wrong?

//Authors Name:  Tom Pitts
//Assignment:    POS 406: Workshop 3              
//Creation Date: September 11, 2004
//Due Date:      September 15, 2004

import java.lang.Math;                  //Import math class
import java.text.DecimalFormat;      //Import decimal formatting class

 class POS406_W3_TRP { //Declare Class
     public static void main(String[] arguments) {
            double rate = .0575;  //Interest rate in decimal format
            double principle = 200000;  //Amount of loan
            double term = 360;      //Term of loan in months
            double monthlyRate = (rate/12);     //Monthly interest rate = .0575/12

            //Loan Overview Output
            System.out.println("Name:         Tom Pitts");
            System.out.println("Assignment:   Workshop 2");
            System.out.println("________________________ \n");
            System.out.println("Principle       : $" + principle);
            System.out.println("Interest Rate   : " + rate * 100 + "%");
            System.out.println("# of Payments   : " + term);

            /*Mortgage Payment Formula provided by Instructor is:
            Principal * rate / ( 1 - (1 + rate)^ -number of payments )*/

            double payments = (principle * monthlyRate) /  (1- Math.pow((1 + monthlyRate), -term));
            DecimalFormat myVar = new DecimalFormat("$###,##0.00");
            String myoutput = myVar.format(payments);
            System.out.println("Monthly Payment : " + myoutput + "\n");
   
      try
      {System.out.println("Press Enter to Continue");
      System.in.read();
      System.in.read();
      }
      catch(Exception error)
      {}
      
            System.out.print("\tPrincipal\tInterest\tLoan\n"); //Amortization Headings
            System.out.println("Months\tPayment\t\tPayment\t\tBalance\n");//Amortization Headings
            int monthCounter=1;  
            double loanBalance=0.0;
            double interestPaid=0.0;
            double principlePayment=0.0;

                  for (;monthCounter <= 360; monthCounter++) { //Intrement monthCounter by 1 each loop
            DecimalFormat balanceVar = new DecimalFormat("$###,##0.00");
            String decimal_Loan_Balance = balanceVar.format(loanBalance);
            String interestPaid_output = balanceVar.format(interestPaid);
            String principlePayment_output = balanceVar.format(principlePayment);

                  if(monthCounter ==1){
                  interestPaid= principle * monthlyRate;
                  loanBalance= principle - (payments - interestPaid);
                                                }
                  else{
                  interestPaid= loanBalance * monthlyRate;
                  loanBalance= loanBalance - (payments - interestPaid);
                                                }
            
            principlePayment = payments - interestPaid;

            System.out.println(monthCounter + "\t" + principlePayment_output + "\t\t"+ interestPaid_output + "\t\t" + decimal_Loan_Balance);

            if(monthCounter % 12==0)

      try
      {System.out.print("Press Enter to Continue");
      System.in.read();
      System.in.read();
      }
      catch(Exception error)
      {}
      }
 }
 }
0
Comment
Question by:nihlcat
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
  • 2
6 Comments
 
LVL 14

Expert Comment

by:sudhakar_koundinya
ID: 12058259
It should be something like this

//Authors Name:  Tom Pitts
//Assignment:    POS 406: Workshop 3              
//Creation Date: September 11, 2004
//Due Date:      September 15, 2004

import java.lang.Math;               //Import math class
import java.text.DecimalFormat;     //Import decimal formatting class

 class POS406_W3_TRP { //Declare Class
     public static void main(String[] arguments) {
          double rate = .0575;  //Interest rate in decimal format
          double principle = 200000;  //Amount of loan
          double term = 360;     //Term of loan in months
          double monthlyRate = (rate/12);     //Monthly interest rate = .0575/12

          //Loan Overview Output
          System.out.println("Name:         Tom Pitts");
          System.out.println("Assignment:   Workshop 2");
          System.out.println("________________________ \n");
          System.out.println("Principle       : $" + principle);
          System.out.println("Interest Rate   : " + rate * 100 + "%");
          System.out.println("# of Payments   : " + term);

          /*Mortgage Payment Formula provided by Instructor is:
          Principal * rate / ( 1 - (1 + rate)^ -number of payments )*/

          double payments = (principle * monthlyRate) /  (1- Math.pow((1 + monthlyRate), -term));
          DecimalFormat myVar = new DecimalFormat("$###,##0.00");
          String myoutput = myVar.format(payments);
          System.out.println("Monthly Payment : " + myoutput + "\n");
   
     try
     {System.out.println("Press Enter to Continue");
     System.in.read();
     System.in.read();
     }
     catch(Exception error)
     {}
     
          System.out.print("\tPrincipal\tInterest\tLoan\n"); //Amortization Headings
          System.out.println("Months\tPayment\t\tPayment\t\tBalance\n");//Amortization Headings
          int monthCounter=1;  
          double loanBalance=0.0;
          double interestPaid=0.0;
          double principlePayment=0.0;

               for (;monthCounter <= 360; monthCounter++) { //Intrement monthCounter by 1 each loop
          DecimalFormat balanceVar = new DecimalFormat("$###,##0.00");
          String decimal_Loan_Balance = balanceVar.format(loanBalance);
          String interestPaid_output = balanceVar.format(interestPaid);
          String principlePayment_output = balanceVar.format(principlePayment);

               if(monthCounter ==1){
               interestPaid= principle * monthlyRate;
               loanBalance= principle - (payments - interestPaid);
                                        }
               else{
               interestPaid= loanBalance * monthlyRate;
               loanBalance= loanBalance - (payments - interestPaid);
                                        }
         
          principlePayment = payments - interestPaid;
      if(monthCounter >1)
          System.out.println((monthCounter-1) + "\t" + principlePayment_output + "\t\t"+ interestPaid_output + "\t\t" + decimal_Loan_Balance);

          if((monthCounter-1) % 12==0)

     try
     {System.out.print("Press Enter to Continue");
     System.in.read();
     System.in.read();
     }
     catch(Exception error)
     {}
     }
 }
 }
0
 
LVL 14

Accepted Solution

by:
sudhakar_koundinya earned 250 total points
ID: 12058286
Small correction

>>for (;monthCounter <= 360; monthCounter++) { //Intrement monthCounter by 1 each loop

for (;monthCounter <= 361; monthCounter++) { //Intrement monthCounter by 1 each loop

0
 
LVL 7

Expert Comment

by:bvanderveen
ID: 12058329
Look at where you format interestPaid_output and principlePayment_output - before you compute the source values.
0
Online Training Solution

Drastically shorten your training time with WalkMe's advanced online training solution that Guides your trainees to action. Forget about retraining and skyrocket knowledge retention rates.

 
LVL 7

Expert Comment

by:bvanderveen
ID: 12058353
Just to be clear - step through with Eclipse debugger.  You are computing the payment and interest correctly, but you have already computed principlePayment_output and interestPaid_output from the values of interest and principle as they were initialized (zero).  Just need to move a few lines...

I wish other homework questions were like this - honest, and looking for debugging help, rather than "do it for me".
0
 
LVL 7

Expert Comment

by:bvanderveen
ID: 12060055
Sudhakar's solution works, but I think it is a kludge.  Instead of printing out.

   System.out.println((monthCounter-1) + "\t" + principlePayment_output + "\t\t"+ interestPaid_output + "\t\t" + decimal_Loan_Balance);

You should move the assignments for those variables after interestPaid and loan_balance have been computed.  Then your program will be more "rational".  

Follow the logic - your teacher should give some points off for this crude workaround - it would be harder to maintain and understand.
0
 
LVL 6

Author Comment

by:nihlcat
ID: 12064712
Ok, understood.  I haven't turned it in yet, so I will review this.  I wanted to clean up the code anyway.  THANK YOU for your opinions!
0

Featured Post

Instantly Create Instructional Tutorials

Contextual Guidance at the moment of need helps your employees adopt to new software or processes instantly. Boost knowledge retention and employee engagement step-by-step with one easy solution.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Apache Camel - Unable to propagate JMS Header Properties between Request - Response 3 41
by zero exception 10 83
Java List 4 76
Java pass by reference 3 74
INTRODUCTION Working with files is a moderately common task in Java.  For most projects hard coding the file names, using parameters in configuration files, or using command-line arguments is sufficient.   However, when your application has vi…
In this post we will learn different types of Android Layout and some basics of an Android App.
Viewers learn how to read error messages and identify possible mistakes that could cause hours of frustration. Coding is as much about debugging your code as it is about writing it. Define Error Message: Line Numbers: Type of Error: Break Down…
This tutorial will introduce the viewer to VisualVM for the Java platform application. This video explains an example program and covers the Overview, Monitor, and Heap Dump tabs.
Suggested Courses

751 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question