for loop help.

[Energizer100]

My assignment is

LoanTable

Background:

When buying a home, a very important financial consideration that many buyers face is obtaining a qualifying loan from a financial institution. Interest rates can be fixed or variable and there are service charges called 'points' for taking out a loan. One 'point' is equal to 1% of the loan amount (called principal) borrowed. Taking out a loan of $150,000 with a 2 point charge will amount to a cost of $3,000 for obtaining the loan - before you ever make your first mortgage payment! Some banks and financial lending institutions offer lower interest rates but require higher points, and vice versa. Usually, the more po ints you pay, the lower the interest rate. It is helpful to know what the monthly mortgage payment will be for a given loan amount with different interest rates.

The monthly payment on a loan is determined using three inputs:

1. The amount of the loan (principal).

2. The number of years for the loan to be paid off.

3. The annual interest rate of the loan.

The formula for determining payments is:

a = (p * k * c)(c - 1)

p = principal, amount borrowed
k = monthly interest rate (annual rate/12.0)
n = number of monthly payments (years * 12)
c = (1 + k)n
a = monthly payment (interest and principal paid)


Assignment:

1. Write a program that prompts the user for the following information:

a. The amount of the loan
b. The length of the loan in years
c. A low interest rate in %
d. A high interest rate in %

2. Print out the monthly payment for the different interest rates from low to high, incremented by 0.25%.


3. A sample run output is given below:

Mortgage problem

Principal = $100000.00
Time = 30 years
Low rate = 11%
High rate = 12%

Annual Interest Rate Monthly Payment

11.00 952.32
11.25 971.26
11.50 990.29
11.75 1009.41
12.00 1028.61

4. Your program should make use of the built-in pow method located in the Math class.

5. Your program must make use of separate methods for the data input section and the printing section of the assignment.




My code is

import java.util.Scanner;

public class LoansTable {

public static void main(String args[])
{
Scanner myScanner = new Scanner(System.in);
double principalAmout;
double lowRate;
double highRate;
int years;
double monthlyPayment;
double k;
double n;
double c;

System.out.println("Enter the amount of the loan you would like to take."); //User Inputs
principalAmount = myScanner.nextDouble();
System.out.println("Enter the length of the loan in years.");
years = myScanner.nextInt();
System.out.println("Enter a low interest rate in %.");
lowRate = myScanner.nextDouble();
System.out.println("Enter a high interest rate in %.");
highRate = myScanner.nextDouble();

System.out.println("Principal = $" + principalAmount);
System.out.println("Time = " + years + " years");
System.out.println("Low Rate = " + lowRate + "%");
System.out.println("High Rate = " + highRate + "%");

for (double lowRate; lowRate <= highRate; lowRate = lowRate + 0.25)
{
k = lowRate / 12.0;
n = years * 12;
c = Math.pow((1 + k), n);
monthlyPayment = (principalAmount * k * c) / (c - 1);
System.out.println("Your Annual Interest Rate is " + lowRate);
System.out.println("Your Monthly Payment is " + monthlyPayment);
}
}
}

the error that shows is that it cannot find symbol principalAmount in the code.

[JosAH]

Compilers are quite picky when it comes to 'principalAmout' vs 'principalAmount'.

kind regards,

Jos

[Energizer100]

Compilers are quite picky when it comes to 'principalAmout' vs 'principalAmount'.

kind regards,

Jos

thank you very much..it was a silly mistake

[Energizer100]

I have another problem. It says that

my for loop thing is not a statement

[Energizer100]

nvr mind
i got it to work

[Energizer100]

I have another problem. I'm trying to make the double round off to 2 decimal places.

import java.util.Scanner; //Imports Input

public class LoansTable //Creates Class
{
public static void main(String args[]) //Main Method
{
Scanner myScanner = new Scanner(System.in); //Creates Scanner
double principalAmount; //Variables
double lowRate;
double annualRate; //I added annualRate in here because lowRate had to be assigned to something in the for loop. And it makes more sense.
double highRate;
int years;
double monthlyPayment;
double k; //k, n, c are the variables given in the assignment. I didn't want the calculation to look like a mess, so I did each part seperately.
double n;
double c;

System.out.println("Enter the amount of the loan you would like to take."); //User Inputs
principalAmount = myScanner.nextDouble(); //principalAmount is assigned to the first number the user inputs

System.out.println("Enter the length of the loan in years.");
years = myScanner.nextInt(); //years is assigned to the second number the user inputs

System.out.println("Enter a low interest rate in %.");
lowRate = myScanner.nextDouble(); //lowRate is assigned to the third number the user inputs. I was a bit confused when the assignment said to ask the user to input the lowRate in %, but after seeing the sample sets, I decided against it.

System.out.println("Enter a high interest rate in %.");
highRate = myScanner.nextDouble(); //highRate is assigned to the fourth number the user inputs.

System.out.println();
System.out.println("Mortgage Problem");
System.out.println();
System.out.println("Principal = $" + principalAmount); //First off, the program will output what the user just inputted
System.out.println("Time = " + years + " years");
System.out.println("Low Rate = " + lowRate + "%");
System.out.println("High Rate = " + highRate + "%");
System.out.println(); //Prints a blank line.
System.out.println("Annual Interest Rate Monthly Payment"); //Prints out Annual Interest Rate and Monthly Payment
System.out.println();

for(annualRate = lowRate; annualRate <= highRate; annualRate += 0.25) //A for loop is the most logical thing to use here. annualRate had to be assigned to lowRate in order for the loop to work correctly.
{
k = annualRate * 0.01 / 12.0; //Here is where I made my calculations seperately. First off is the k calculation
n = years * 12; //And then the n
c = Math.pow((1 + k), n); //And then the c, which uses a Math.pow
monthlyPayment = (principalAmount * k * c) / (c - 1); //This main calculation looks much neater than putting all of them together
System.out.print(" " + annualRate);
System.out.println(" " + monthlyPayment); //These last two lines will output the monthly payment and the annual interest rate in table form. There was a lot of spacing in between.
}
}
}

[JosAH]

I have another problem. I'm trying to make the double round off to 2 decimal places.

Have a look at the DecimalFormat class or use the printf() method
from the PrintStream class (it basically uses a same DecimalFormat object to
do the hard work).

kind regards,

Jos

[Energizer100]

Have a look at the DecimalFormat class or use the printf() method
from the PrintStream class (it basically uses a same DecimalFormat object to
do the hard work).

kind regards,

Jos

I looked it up, both of them. But I still don't understand how to actually use it in my program.

[JosAH]

I looked it up, both of them. But I still don't understand how to actually use it in my program.

Did you actually read the API documentation for those classes and methods?
Armed with one of them you can easily print a floating point number rounded
to any number of decimal positions.

kind regards,

Jos