I'm trying to program something that repeats itself until it gets the amount right. My program is basically a loan program that helps you figure out how long it'll take for you to pay off a loan with interest. So far, I managed to get the first month to print out (although not exactly right...), but I need it to keep repeating until the loan amount has been paid off. I hope that makes sense.
import java.util.*;
import java.io.*;
public class Project4{
static Scanner console = new Scanner(System.in);
public static void main(String[] args) throws FileNotFoundException
{
Scanner keyboard = new Scanner(System.in);
Scanner user_input = new Scanner(System.in);
Scanner scan = new Scanner(System.in);
PrintWriter outFile = new PrintWriter("Project4.out");
double lamnt;
double mpay;
double intrestrate;
double mnthintrest;
double mintrestrate;
System.out.print("Enter the Loan Amount: ");
lamnt = keyboard.nextDouble();
System.out.println();;
System.out.print("Enter the intrest rate (Ex:5.75): ");
intrestrate = keyboard.nextDouble();
System.out.println();
System.out.print("Enter the monthly payment you want to make: ");
mpay = keyboard.nextDouble();
System.out.println();
mintrestrate = intrestrate/12;
mnthintrest = lamnt*mintrestrate;
System.out.println("The first month intrest rate is:" + pay);
}
}
I was suggested using a while loop but I'm not too sure how to make the while loop keep going until the loan amount is paid off. Also yes I know the outcome isn't right, I'm working on that part. I'm not too sure how to space out the titles properly.
I need the output to look like this: (using 1000 in loan payment, 7.2 in interest rate, 25 for monthly pay)
Amount loan after payment #1 is: 981.00 Principle is: 19.00 Interest is: 6.00
Amount loan after payment #2 is: 961.89 Principle is: 19.11 Interest is: 5.89
So, if you want to use a while loop until your loan is paid off, just do something like:
while (lamnt > 0) {
// Do stuff to pay off the loan here.
}
As long as you're updating the lamnt within the loop, that should work.
Hope that helped!
;)
Edit: Also, make sure you're only creating scanners that you actually use. And don't forget to close them at the end of the scope!
Assuming that interest rate would be entered in percentage, the mnthintrest calculation would need an additional multiplication by 1/100 i.e. 0.01
mnthintrest = lamnt*mintrestrate*(0.01);
You also need to edit the variable pay to mpay
System.out.println("The first month intrest rate is:" + pay);
I think your logic for money paid per month should be ( as others suggested) - reducing the loan amount until it reaches zero.
Now coming to implementation, you will be reducing the amount and since we wouldn't want the original data ( variable) to be affected, we could first store it an temporary variable.
For keeping track of #number of payment, we can keep the month count in another variable.
You could think of something like this:
double temp = lamnt;
int monthNumber = 1;
while(temp>0){
mnthintrest = temp*mintrestrate*0.01;
double principlePaidPerMonth= mpay- mnthintrest;
temp = temp - principlePaidPerMonth; // reducing the principle amount paid before printing
System.out.println("\nAmount left after payment "+monthNumber+" is:" + temp);
System.out.println("This month intrest is:" + mnthintrest);
System.out.println("Principle paid is:" + principlePaidPerMonth);
monthNumber++;
}
// text to be printed could be different
It is a good practice to keep variable names as meaningful as possible and to declare the variables as much closer to their first use.
So you could declare the variables for interest and interest rate just at the time of initializing above where the while loop part starts.
double mintrestrate = intrestrate/12;
double mnthintrest = lamnt*mintrestrate;
For formatting, you could use System.out.printf() instead of println - this could help format the number of digits shown after decimal
For getting precision - you could use absolute/ceiling functions available in Math class.
Related
I'm really new to Java so please excuse if this isn't the 100% right way to even write this code.
So I've been messing around with this code for about 6 hours now, and I can not for the life of me figure out how to fix this issue:
I have a compound interest calculator that takes user input for the variables of term length, initial amount, and APR. I can get the answer I want if it was just the simple one time calculation, but I really want it to show me the amount increased each year of a term. For example:
If the interest is calculated for 10 years, I want it to show me the amount for each year leading up to it. Right now all I get is a static number of 1, or infinity.
How do I get this program to show me the total amount for the term (i.e. the length of the user input investment), broken down per year with the amount shown per year?
The code is:
import java.util.Scanner;
import java.lang.Math;
public class CompoundInterestCalculator {
public static void main(String args[]) {
Scanner scan = new Scanner(System.in);
double initial; // the intial amount your loan is set for
int term; // the number of years you want to calculate
float yearlyrate; // interest rate
int repeat;
// System message to alert users to program use
System.out.printf("Hi there! I can calculate compound interest for you at a fixed interest
rate and term.\n\nPlease enter numbers without commas or symbols to get an accurate result!");
// Prompt for initial investment amount
System.out.println("\nPlease enter your initial investment.");
// Store value of user input for initial investment
initial = scan.nextDouble();
// Prompt for interest percentage
System.out.println();
System.out.println("Please enter the annual interest percentage.");
System.out.println();
// Store value of user input for interest amount
yearlyrate = scan.nextFloat();
// Prompt for length of the term for investment
System.out.println();
System.out.println("Please enter the length of your investment in years.");
// Store Value of user input for term length
term = scan.nextInt();
//For loop to set up calulations, repeats, and totals
for(repeat = 0; repeat < term; repeat++) {
System.out.println();
System.out.println("Your investment amount after" + (repeat+1) + "years is:");
// calculation for determining compound interest at a yearly rate and over the term
double total = Math.pow(initial * (1 + (yearlyrate/100) / 12) , 12/term);
// Displays the total value to the user
System.out.println("$" + total);
// Seperation line to clean it up
System.out.println();
// Close the scanner
scan.close();
}
}
}
Any help would be greatly appreciated because I am really out of my depth with this one.
Just a small change in your calculation logic:
// calculation for determining compound interest at a yearly rate and over the term
double total = initial * Math.pow((1 + (yearlyrate/100)) , (repeat+1));
This question already has answers here:
How to round a number to n decimal places in Java
(39 answers)
Closed 6 years ago.
When running my program, the last line displaying yearly gas expense is not showing... what have I done wrong? Also would like some help rounding figures to 2 decimal points...
I tried implementing a few strategies but none of them worked.
Any help is appreciated!
public class GasExpenses {
public static void main(String[] args) {
//Use scanner in order to retrieve user input.
Scanner keyboard= new Scanner(System.in);
//Declare variables.
int milesPerWeek;
double milesPerGallon,costOfGas;
System.out.println("GAS EXPENSES");
//Get user input.
System.out.println("How many miles do you drive a week?");
milesPerWeek = keyboard.nextInt();
//Get user input.
System.out.println("How many miles per gallon does your auto get?");
milesPerGallon=keyboard.nextDouble();
//Get user input.
System.out.println("What is the current cost of gas?");
costOfGas=keyboard.nextDouble();
//Calculate miles per year.
int milesPerYear=(milesPerWeek*52);
//Display calculated yearly mileage.
System.out.println("At " + milesPerWeek + "miles per week, you travel "+
milesPerYear + " miles per year.");
//Calculate and display calculated weekly & yearly gallons of gas used.
double gallonsPerWeek=(milesPerWeek/milesPerGallon);
System.out.println("Gallons per week:" + gallonsPerWeek);
double gallonsPerYear=(gallonsPerWeek*52);
System.out.println("Gallons per year:" + gallonsPerYear);
//Calculate and display calculated weekly & yearly gas expense.
System.out.println("With gas at $" +costOfGas + " per gallon, you will
spend: ");
double weeklyGasExpense=(costOfGas*milesPerWeek);
System.out.println("Gas expense per week: $" +weeklyGasExpense);
double yearlyGasExpense=(costOfGas*milesPerYear);
System.out.println("Gas expense per year: $" +yearlyGasExpense);
//Calculate and display calculated weekly & yearly gas expense based on
increased gas price.
double costIncrease= (costOfGas+1);
System.out.println("If gas goes up by one dollar per gallon to $" +
costIncrease +(" per gallon, you will spend:"));
double weeklyIncreasedGas=(costIncrease*milesPerWeek);
double yearlyIncreasedGas=(costIncrease*milesPerYear);
System.out.println("Gas expense per week : $" +weeklyIncreasedGas);
System.out.print("Gas expense per year : $" +yearlyIncreasedGas);
}}
Run system.out.flush() at the end of your code to make sure everything is printed.
For the rounding you could try this answer round up to 2 decimal places in java?
For first question, this line works for me given your code:
System.out.print("Gas expense per year : $" +yearlyIncreasedGas);
For second do this:
double number = 111.12345;
double result = Math.round(number * 100.0) / 100.0;
JAVA OUTPUT Question, please help.
How to format two outputs, first is to have an ouput using HALF_UP rounding and currency formating and the second is to have an ouput with precentage?
Supporting docs:
(A) orginal assignment
Introduction to Object-Oriented Programming
Programming Assignment – Discount Coupon
A supermarket awards coupons depending on how much a customer spends on groceries. For example, if you spend $50, you will get a coupon worth eight percent of that amount. The following table shows the percent used to calculate the coupon awarded for different amounts spent. Write a program that calculates and prints the value of the coupon a person can receive based on groceries purchased and the amount paid after the discount is applied.
Money Spent
Coupon Percent
Less than $10
No coupon
Between $10 and $60
8%
Between $61 and $150
10%
Between $151 and $210
12%
More than $210
14%
Note, as specified, it is not clear how to handle boundary conditions. For example, what is the coupon percent for $150.25? You should decide how you are going to handle boundary conditions and be sure to explain your choice in the program documentation.
Your program should use a currency instance for formatting dollar amounts and a percent instance for formatting percents. They can both be found in the java.text.NumberFormat package. Use the HALF_UP rounding mode for your currency displays.
Here is a sample run:
run:
Please enter the cost of your grocies: 78.24
You earned a discount of $7.82. (10% of your purchase)
Please pay $70.42. Thank you for shopping with us!
(B) code so far
import java.util.Scanner;
import java.text.NumberFormat;
public class Coupon {
/**
* #param args the command line arguments
*/
public static void main(String[] args) {
// TODO code application logic here
Scanner input = new Scanner(System.in);
NumberFormat currency = NumberFormat.getCurrencyInstance();
//Variables
double amountSpent=0;
double couponAmount = 0;
double totalAfterCoupon= 0;
final double lessThanTen = 0.00;
final double betweenTenAndSixity = 0.08;
final double betweenSixtyOneAndOneHundredAndFifty = 0.10;
final double betweenOneHundredAndFiftyOneAndTwoHundredAndTen = 0.12;
final double overTwoHundredAndTen = 0.14;
System.out.print("Please enter the cost of your groceries: ");
amountSpent = input.nextDouble();
if (amountSpent<10 && amountSpent>=0)
{
couponAmount = lessThanTen * amountSpent;
System.out.printf("You earned a discount of ", currency.format(couponAmount), "(0% of your purchase)");
}
else if (amountSpent>=10 && amountSpent<=60.49)
{
couponAmount = betweenTenAndSixity * amountSpent;
System.out.printf("You earned a discount of ", currency.format(couponAmount), "(10% of your purchase)");
}
else if (amountSpent>=60.50 && amountSpent<=150.49)
{
couponAmount = betweenSixtyOneAndOneHundredAndFifty * amountSpent;
}
else if (amountSpent>=150.50 && amountSpent<=210)
{
couponAmount = betweenOneHundredAndFiftyOneAndTwoHundredAndTen* amountSpent;
}
else if (amountSpent>210)
{
couponAmount = overTwoHundredAndTen* amountSpent;
}
else
{
System.out.println("Please enter your total bill between $0.00 or greater. ");
}
System.out.printf("the coupon amount is: %f ", couponAmount);
}
}
Note: I notice you're a newcomer and I'm gonna give you this one for free (We've all need to learn things first), but please keep in mind that ther are certain rules in SO; Asking for homework corrections or bad research related questions aren't appreciated, specially if they both apply. Also as tnw mentioned you should narrow your question down to the specific part of code that's relevant, so that it can easily be reproduced or/and found by others that have the same issue.
In case of the answer to your formatting problem you have some amazing resources at Oracle's official docs, learn how to use their docs and you'll get the hang of Java in no time. On the NumberFormat class they have this: https://docs.oracle.com/javase/tutorial/i18n/format/numberFormat.html , and you will also need the info on locale's in Java: https://docs.oracle.com/javase/8/docs/api/java/util/Locale.html .
What you need to do to use the NumberFormat class is create an instance of the locale you're going to use like: Locale enUSLocale = new Locale.Builder().setLanguage("en").setRegion("US").build();
There are multiple other ways to do this.
And then use this locale to indicate the NumberFormat class what to use:
//Instantiate the NumberFormat:
NumberFormat USFormat = NumberFormat.getCurrencyInstance(enUSLocale);
//And print it:
System.out.println("You earned a discount of " + USFormat.format(couponAmount));
Well I hope this gives you the basis you need to go on and learn to use the docs and other info online!
Goo(gle)d Luck!
My while statement just doesn't seem to make sense to me, even though it works.
I want it to calculate the interest only as long as the countYears is less than the timeLimit....so if I set timeLimit to 5, it should only calculate 5 years worth of interest but the way I read the current while statement, it doesn't seem to say that. Maybe I am just reading it wrong?
public class RandomPractice {
public static void main(String[] args)
{
Scanner Keyboard = new Scanner(System.in);
double intRate, begBalance, balance;
int countYears, timeLimit;
System.out.println("Please enter your current investment balance.");
begBalance = Keyboard.nextDouble();
System.out.println("Please enter your YEARLY interest rate (in decimals).");
intRate = Keyboard.nextDouble();
System.out.println("Please enter how long (in years) you would like to let interest accrue.");
timeLimit = Keyboard.nextInt();
balance = begBalance * (1 + intRate);
countYears = 0;
/* The way I read this while statement is as follows
* "While countYears is GREATER than the timeLimit...calculate the balance"
* This makes no logical sense to me but I get the correct output?
* I want this code to calculate the investment interest ONLY as long as
* countYears is LESS than timeLimit **/
while (countYears >= timeLimit)
{
balance = balance + (balance * intRate);
countYears++;
}
System.out.println(balance);
}
}
That code you have, as it stands, does not generate the correct data, my transcript for eight years at one percent per annum follows:
Please enter your current investment balance.
100
Please enter your YEARLY interest rate (in decimals).
.01
Please enter how long (in years) you would like to let interest accrue.
8
101.0
In other words, only one year of interest is added rather than eight years.
So either your compiler is totally screwy, your code is not what you think it is, or whatever test data and/or method you're using to check the interest calculation is lacking somewhat.
First, as you foreshadowed, you need to change the condition to be countYears < timeLimit.
In addition, you also need to remove the initial interest calculation before the loop since this would mean you'd get a full year's interest as soon as you deposit the money. With those two changes:
balance = begBalance;
while (countYears < timeLimit) {
balance = balance + (balance * intRate);
countYears++;
}
and you then get the correct value of:
Please enter your current investment balance.
100
Please enter your YEARLY interest rate (in decimals).
.01
Please enter how long (in years) you would like to let interest accrue.
8
108.28567056280801
Your loop isn't being executed at all if you switch it to <= it will be correct.
Right now your output is what is calculated outside of the loop.
This is my homework it is due Monday the 16th.
I finally got the months to display right but the amounts are wrong.
Also, not necessary but it would be nice to stop and Print something between each loan.
Like loan 1, loan 2, loan 3...
Any help will be appreciated
/*Write the program in Java (without a graphical user interface)
and have it calculate the payment amount for 3 mortgage loans:
- 7 year at 5.35%
- 15 year at 5.5%
- 30 year at 5.75%
Use an array for the different loans.
Display the mortgage payment amount for each loan
and then list the loan balance and interest paid for
each payment over the term of the loan.
Use loops to prevent lists from scrolling off the screen.*/
I have the months correct but the loan amounts are wrong.
import java.io.IOException; //Code that delays ending the program
class MonthlyRhondav4
{
public static void main ( String[] args) throws IOException{
double loanAmount = 200000.00; // $ amount borrowed
double monthlyPayment = 0; // monthly payment for calculating
double loanBalance;
double interestPaid;
double principalPaid;
int paymentCounter;
int lineCounter = 0;
java.text.DecimalFormat dcm = new java.text.DecimalFormat("$,###.00");
int termArray[] = {84, 180, 360}; // Different loan terms in months
double interestArray[] = {0.0535, 0.055, 0.0575};// Different interest rates for the loan
int k =0;// gonna be paymentIndex
/*Code to start the payment list*/
System.out.print("\n\nPlease Press Enter to Continue to the 3 Different Amortization Lists");
System.out.println ();
System.out.println ();
System.in.read();
System.in.read();
/*Display columns*/
System.out.println("Month \t Loan Amount Left\tInterest\t\tPrincipal \n"); //Prints headers for columns
System.out.println ();
/*Loop to calculate and print monthly payments*/
//for(k=0; k<3; k++){// k is going to be paymentIndex to loop through index
for (k = 0; k < interestArray.length; k++) {
for(paymentCounter =1; paymentCounter <= termArray[k]; paymentCounter++) // months through array
{
/********TROUBLE HERE***************************************************************************************/
monthlyPayment = ((loanAmount * (interestArray[k]) * termArray[k]) + loanAmount) / (termArray[k] * 12);
interestPaid = loanAmount*(interestArray[k]/12); //interest paid through array
principalPaid = monthlyPayment-loanAmount*(interestArray[k]/12); //principal paid
/*need to fig monthly payment+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/
System.out.println(paymentCounter + "\t" + dcm.format(loanAmount) + "\t\t" + dcm.format(interestPaid) + "\t\t\t" + dcm.format(principalPaid));
lineCounter++; //Increment the display counter
if (lineCounter > 11 && paymentCounter < termArray[k]*12) //Check to see if 12
{
System.out.println ("Please Press Enter to Continue the List" ); //Code to delay ending the program
System.in.read();
System.in.read();
lineCounter = 0;
}
}
loanAmount = (loanAmount - (monthlyPayment-loanAmount*(interestArray[k]/12))); //Calculate new loan amount
}
}//ends public static void main
}//ends public class
One observation -- you're not doing anything with the loan balance. The reason why nothing is changing is that having computed the interest and principal amounts of a given payment, you're not reducing the loan balance by the principal portion of the payment. You need to change your code to display the current loan balance and to compute the principal/interest split from the current loan balance and not the original loan amount.
Edited
Ok -- I see you were trying to update the balance, but you have it outside the loop for the loan. That needs to be inside the loop so that it is updated for each payment. Also, you have things like loanAmount * (interestArray[k] / 12) over and over again. Consider using variables, such as
double interestPaid = loanAmount * (interestArray[k] / 12)
This will make your code easier to read and more maintainable since if you find a mistake in the calculation, you only have to fix the mistake in one place rather than having to fix it everywhere you had the calculation.
I also don't see where you're calculating the monthly payment. That's a function of the original loan amount, number of payments, and interest rate. Remember, the monthly payment is fixed and the interest/principal split of each payment will change as the loan is paid down. You might find http://en.wikipedia.org/wiki/Mortgage_calculator useful to figure out the formula for the monthly payment.
first : never ever use double to calculate something... That's an advice you have to remember. If you don't want to trust me, please search Google for "java double computation" or something like that, and you'll see. Or read the excellent book "Effective Java"
BigDecimal class is there to have correct numbers in Java
A lot of mistakes. For instance you never set the monthlyPayment to anything but 0. You also do not use loanBalance. loanAmount should be a constant. You can also simplify redundant calculations. Example:
interestPaid = loanBalance*(interestArray[k]/12);
principalPaid = monthlyPayment-interestPaid;
instead of
interestPaid = loanBalance*(interestArray[k]/12);
principalPaid = monthlyPayment-loanBalance*(interestArray[k]/12);
I am also not sure you have the correct interest rate formulas, but am not going to check until you remove some of the more obvious errors.