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Assignment 2
Manipulating Numeric Data EE312 - The University of Texas at Austin - Spring 2008 Assigned: Tuesday, Jan. 29 Due: Thursday February 7 before midnight. Value: 20 points (for correctness of the program) File submitted: submit (upload) the final version of your C source code file (.c file) to the Blackboard's assignment manager for this assignment of your section of this course. Purposes: to learn how to input and output numeric values using formatted IO commands to learn how to define and symbolically manipulate numeric data to learn how to use program control statements to perform looping and decision making
The problem: We take a loan for many things that we buy. For this assignment we will create a simplified loan banking information system. The system will provide the following capabilities to the customer (user). 1. Case 1: It will calculate and report the estimated monthly installment (EMI) for the required loan principal for a loan of a given term. The borrower will pay simple interest on the loan of a fixed rate of 20% of the loan amount. [Economics note: In this example, we're using simple interest to keep the calculations relatively straightforward. Real loans are based on compounding interest.] 2. Case 2: In the case that the customer wants to pay more than the EMI each month (e.g., a fixed percentage of EMI additionally) then the system will calculate the way that the monthly payments correspondingly decrease over the term of the loan. [Economics note: In this example, there is no real benefit to the borrower in paying early on his loan. This is because, to keep the example simple, we're not recalculating the interest when the borrower prepays. In the real world with compounding interest, the amount paid to the lender would reduce if the borrower pre-paid.] Your program will need to perform the following input, process, and output steps repeatedly until the customer decides that no more operations are needed (Case 3). Inputs: Your program should input values from the keyboard using scanf( ). Use appropriate prompt messages (i.e., output messages) to tell the user what needs to be input at any point in the dialog. Your program should work correctly for all legitimate values that are input (defined below). If a bad input value is given then your program should either: terminate or give a bad output value. Given that the user wants to potentially do two different operations with the system, there are two different sets of numeric inputs the user might give your program. To start with, the user inputs (when prompted) a 1 to calculate the EMI for a new loan, or a 2 to calculate monthly payments given that he wants to prepay his loan, or a 3 to end the program. Subsequent inputs should depend on this selection:
Page 2 of 3 1. Case 1: To calculate the EMI, your program should request the value of the principal loan amount (as a float) and the number of months of the loan term (as an integer) 2. Case 2: To calculate new EMI amounts given prepayments, the user should be asked to input the value of the principal (as a float), the number of months in the term of the loan (as an integer) and the percentage of the EMI the user intends to prepay each month (as a float). 3. Case 3: The customer has finished using the system for EMI operations, and wishes to terminate the program. Your system should output a goodbye/thank you message in that case and then terminate. Processing: The following information provides some details about the expected behavior of your program and some hints about the design of the algorithm. 1. The basic EMI can be calculated using the following equation (which assumes 20% simple interest). This is formula not in C. EMI = (Principal +Principal*20/100)/Term 2. Our bank is a nice bank that reduces the borrower's EMI when he pays early. Your program should assume that the borrower intends to prepay by EMI*PrepayPercentage each month and calculate the remaining payment amounts for the term of the loan. 3. The following high-level algorithm might give you some idea about how to calculate a set of monthly payments given that the borrower is paying on his loan balance early: Calculate the loan Balance (assuming 20% simple interest) Calculate the following for Each Month of the term: Calculate the new EMI Calculate the Prepayment (EMI * PrepayPercentage) Calculate the Payment Calculate the remaining Balance 4. Tip: When your borrower pays down his loan early, be careful that he isn't instructed to pay beyond the balance of his loan! If you can accept the above inputs and produce the correct outputs (exemplified below), you may perform the processing in any manner that you want. Outputs: The results of output using printf( ) should show in the terminal window in a form that is understandable by an ordinary human being. They should provide the information described next for each case. 1. Case 1: The program should output to the screen the EMI (as a float) and the total amount paid by the borrower (again, as a float). A sample output might be (user inputs are shown in bold):
Good morning! Welcome to the EE312 Bank. Please select from the following choices: Press 1 to calculate the EMI for a new loan. Press 2 to calculate payment amounts for prepaying a loan. Press 3 to exit. 1
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Enter the loan's principal: 100000.00 Enter the loan's term (in months): 6 Thank you. Your estimated monthly payment (EMI) for each month is: $20000.00
2. Case 2: In the second case, the program should output a list of the borrower's payments for each month in the term of the loan (with the prepayment amount included) and the balance remaining at the end of that month. A sample output might be (user inputs are shown in bold):
Good morning! Welcome to the EE312 Bank. Please select from the following choices: Press 1 to calculate the EMI for a new loan. Press 2 to calculate payment amounts for prepaying a loan. Press 3 to exit. 2 Enter the loan's remaining principal: 100000.00 Enter the number of months remaining on the loan's term: 6 Enter the intended percentage of prepayment: 10.0 Thank you. Here are your calculated payment amounts and the balance at the end of each month: Month Payment Amount Remaining Balance 1 22000.00 98000.00 2 21560.00 76440.00 3 21021.00 55419.00 4 20320.30 35098.70 5 19304.29 15794.42 6 15794.42 0.00
Additional considerations: Write your program using appropriate C language constructs: e.g., constants, variables, declaration statements, assignment statements, input/output methods, numeric expressions and other required "plumbing" to do the computations. As part of the required documentation header block, the top four lines of the file that is submitted should be comments with the following information: // your name - last name, first name // your student EID // your unique section number // EE312-Assignment n - where n is the assignment number (1, 2 ...) You will lose points if you forget to include the header documentation in your submitted file. Along with the required header information also be sure to put comments in your program that would assist in your explaining what your program does. You will not be required to follow the C programming language style guidelines on this assignment, but you will on the next one. Remember that no late assignments will be accepted. Turning in something is always better than nothing.