CSCI 1103 Project 1: Input Money / Output Money

Create a file named LoanCalc.java which will contain a main() method where the action happens. The program should do the following.

1. Prompt the user for the three necessary pieces of information
   • The loan amount
   • The yearly interest rate as a percentage
   • The loan term in years

   Use output messages identical to those in the demo to ensure that you are compatible with the tests.

2. Compute the monthly interest rate by dividing the yearly interest rate by 12 and then by 100 to get the decimal value
3. Compute the number of monthly payments by multiply the years of the loan term by 12
4. Compute the numerator of the right side of the MONTHLY LOAN PAYMENT FORMULA above
5. Compute the denominator of the formula
6. Compute the monthly payment by dividing the numerator by the denominator
7. Print out the monthly payment
8. Print out the total cost of the loan which is the monthly payment multiplied by the number of monthly payments
9. Compute the total interest on the loan which is the total cost minus the loan amount

A few notes

• While the description of the code above is fairly detailed, there may be a few steps that require several lines of code such as the first one. Always break complex tasks into smaller, simpler steps to stay sane.
• In step 5, the denominator requires raising a number to a power. This will be discussed in lecture but is best accomplished with a call to Math.pow() as demonstrated below.

  double twoToFive = Math.pow(2.0, 5.0);
  double x = 3.1;
  double y = 6.8;
  double xToY = Math.pow(x, y);
  

• A common mistake is to forget that the interest rate read from the user is a percentage that needs to be converted to a decimal/fraction number. This is done just by dividing by 100 as indicated in step 2.
• The values printed in this program should appear nicely as dollars with two digits of cents; see the examples below. This will require the use of the printf() method as discussed in lecture.

The LoanCalc program in demonstrated below. Use the samples to more easily generate the required output messages. Lines that start with numbers are the typed by the user.

> javac LoanCalc.java

> java LoanCalc
Enter Loan Amount:
225000.00
Enter Yearly Interest Rate (percent):
7.8
Enter Years for Loan:
30
Monthly Payment is $1619.71
Total Cost for loan is $583095.11
Total Interest for loan is $358095.11

> java LoanCalc
Enter Loan Amount:
1000
Enter Yearly Interest Rate (percent):
10
Enter Years for Loan:
1
Monthly Payment is $87.92
Total Cost for loan is $1054.99
Total Interest for loan is $54.99

The criteria below will be examined by graders to account for part of your grade.

In the file MakeChange.java write a main() method which.

1. Prompts the user for the number of cents required, an integer
2. Prints out the number of each type of bill/coin required to make the change. This should the minimum possible which is determined by the process described above.

There are several ways one can go about this problem all rely on the principle that large bills/coins are given first and then deducted from the running total. The required approach is to use the modulo operator % to get remainders after dividing out large-ish coins. Recall that integer division with / returns a quotient while modulo with % returns a remainder. This enables something like the following.

int centsLeft = 367;
int dollars = centsLeft / 100;  // 3 dollars
centsLeft   = centsLeft % 100;  // 67 cents left

The criteria below will be examined by graders to account for part of your grade.

Run the tests associated with the project and ensure all of them pass. This can be done in DrJava by pressing the Test button when test files are open.

On the command line you can run all tests with the following commands.

On Unix/Mac platforms, use a terminal to run the following commands in the folder where your code exists.

> javac -cp .:junit-1103.jar P1Tests.java   #compile
> java -cp .:junit-1103.jar P1Tests         #run tests

On windows, use cmd.exe and change to the correct directory. Run the commands below where which use a semicolon (;) rather than a colon (:).

> javac -cp .;junit-1103.jar P1Tests.java   #compile
> java -cp .;junit-1103.jar P1Tests         #run tests

Correctly passing all tests will yield output similar to the following.

JUnit version 4.12
..........
Time: 0.024

OK (10 tests)

Failing some tests will yield long messages which hint at where there might be a problem. Failures always end with the number of tests passed/failed as in the following.

FAILURES!!!
Tests run: 10,  Failures: 5

Some policies to keep in mind with respect to how automatic tests affect grades.

• Credit on this section is proportional to the number of tests passed.
• If there were 30 total tests for the project…
• Passing 30 / 30 tests gets 30 / 30 * 50 = 50.00
• Passing 15 / 30 tests gets 15 / 30 * 50 = 25.00
• Passing 4 / 30 tests gets 4 / 30 * 50 = 6.67
• A 5% penalty may be deducted from this portion if code does not compile initially but a grader is able to quickly fix the problem.
• Passing no tests because code does not compile or does not work properly gets 0 credit.

Once your are confident your code is working, you are ready to submit. Ensure your folder has all of the required files. Create a zip archive of your lab folder and submit it to blackboard.

On Canvas:

• Click on the Assignments section
• Click on the appropriate link for this lab
• Scroll down to "Attach a File"
• Click "Browse My Computer"
• Select you Zip file and press OK

You may wish to review the policy on late project submission which will cost you late tokens to submit late or credit if you run out of tokens. No projects will be accepted more than 48 hours after the deadline.

http://www-users.cs.umn.edu/~kauffman/1103/syllabus.html#late-projects