My little program... help pls!

Hi everyone!

As i have left my programming module to the last minute, I have been programming now for a few hours(literally) and I must say I am pretty damn good at it!


This is a program I need to tackle, it is a basic loan repayment thing.

I have corrected all the errors so now it runs, but how do i get it to stop on the remaining months?


you'll see what i mean when you run it:

Code:

#include <stdio.h>
#include <conio.h>

		int main()


	{

   	float loan, rate, payment;
      int month=0;


     printf ("Amount of loan		       =		");
     scanf("%f", & loan);
     printf("Monthly interest rate		=		");
     scanf("%f", & rate);
     printf("Payment per month			=		");
     scanf("%f", & payment);


     while (loan>0.0)
     {
     month++;
     	loan=loan+(loan*rate/100);
      loan=loan-payment;
      printf("In month %d the sum remaining is =  %f\n", month, loan);
     }
     printf("It will take %d months to pay\n", month);
     getch();


   }

Take a look at what your loop does. Say you enter the following data.

loan = 3.33
rate = 3.1
payment = 0.33

(I like three's)

So on month twelve, loan will equal 0.093329. The next iteration of the loop will begin and since 0.093329 is greater than 0 it will perform the calculations again and print a negative value (in this case, ~-0.233). What you want to do is check to make sure that your loan is greater than 0 BEFORE you make your calculations, instead of afterwards.

What you could do is add a little if statement in your loop. Something like...

Code:

if(loan <= 0.0f)
  printf("You have completed your loan payments! FREEDOM!\n");
else
  printf("In month %d the sum remaining is =  %f\n", month, loan);

>What you want to do is check to make sure that your loan is greater than 0 BEFORE you make your calculations

I echo that.

>I have been programming now for a few hours(literally)

Try going for 48 or 72 hours without stopping except for sleeping and eating

About your code. I used to use conio.h as well, but it is a non-standard header file, so you might want to not include that file. Instead of using getch(), which is a function inside conio.h, you can use getc() or getchar() in stdio.h.

Oh....and remember to return 0 at the end of your main function.

Indentation - why is int main the most indented line of the program?

You also should think about the case when the payment is not enough to pay the loan...
You should somehow prevent the infinite loop

an IF statement solves it very easily indeed.

cheers guys

Originally Posted by DavidP

Oh....and remember to return 0 at the end of your main function.

If main() gets to the closing brace and there's no explicit return statement, it returns 0 automatically.