C programming - Breaking down of money

Question

I need to break down the amounts on their respective bill/coin.

The output is somewhat like this:

So far, here is my code: (I made the last few codes a comment one 'cos the errors come from there)

  { 
  int x,y;

  printf("Enter input: ");
  scanf("%d",&x);

  y=x/1000;
  printf("\n# of $1000 bill: %d",y);
  x = x%1000;

  y=x/500;      
  printf("\n# of 4500 bill: %d",y);    
  x = (x%500);

  y=x/200;
  printf("\n#. of $200 bill: %d",y);    
  x = (x%200);

  y=x/100;
  printf("\n# of $100 bill: %d",y);    
  x = (x%100);

  y=x/50;
  printf("\n# of $50 bill: %d",y);    
  x = (x%50);

  y=x/20;
  printf("\n# of $20 bill: %d",y);    
  x = (x%20);

  y=x/10;
  printf("\n#. of $10 coin: %d",y);    
  x = (x%10);

  y=x/5;
  printf("\n#. of $5 coin: %d",y);    
  x = (x%5);

  y=x/1;
  printf("\n# of $1 coin: %d",y);    
  x = (x%1);


  getch();
  return 0;
  }

I hope you'll help me out with this. :/

Thanks!

Answer 1

.25 and .01 aren't numbers. Read up in C documentation how do you write floating point numbers...

Answer 2

It's a simple heuristic problem. You already have the right idea. For a start, if you want to use int (and that's probably a good idea in your case to avoid fp-precision headaches and the need to use a separate fmod), you'll have to scale the floating-point input and your modulo/divisors by 100. Also to cut down on some redundancy, consider using a function like:

// returns number of units and subtracts unit_size * result
// from val
int units(int* val, int unit_size)
{
    int num = *val / unit_size;
    *val %= unit_size;
    return num;
}

printf("No. of P1000 bill: %d\n",units(&x, 1000 * 100) );
printf("No. of P500 bill: %d\n",units(&x, 500 * 100) );
printf("No. of P200 bill: %d\n",units(&x, 200 * 100) );
etc.

That should cut down on redundant code a little bit. Maybe not worth getting too fancy for it and I suspect this is homework. Complete solution:

// returns number of units and subtracts unit_size * result
// from val
int units(int* val, int unit_size)
{
    int num = *val / unit_size;
    *val %= unit_size;
    return num;
}

int main()
{
    printf("Enter input: ");

    float amount;
    scanf("%f",&amount);
    int x = (int)(amount * 100.0 + 0.5);

    printf("No. of P1000 bill: %d\n", units(&x, 1000 * 100) );
    printf("No. of P500 bill: %d\n", units(&x, 500 * 100) );
    printf("No. of P200 bill: %d\n", units(&x, 200 * 100) );
    printf("No. of P100 bill: %d\n", units(&x, 100 * 100) );
    printf("No. of P50 bill: %d\n", units(&x, 50 * 100) );
    printf("No. of P20 bill: %d\n", units(&x, 20 * 100) );
    printf("No. of P10 coin: %d\n", units(&x, 10 * 100) );
    printf("No. of P5 coin: %d\n", units(&x, 10 * 100) );
    printf("No. of P1 coin: %d\n", units(&x, 1 * 100) );
    printf("No. of 25 cents: %d\n", units(&x, 25) );
    printf("No. of 1 cent: %d\n", units(&x, 1) );

    return 0;
}

[Edit] If you have trouble understanding pointers, then just do it the way you wrote without using the units function but modify it accordingly to read in a float and multiply by 100 as in the example above.

[Edit] Requested:

int main()
{
    printf("Enter input: ");

    float amount;
    scanf("%f",&amount);
    int x = (int)(amount * 100.0 + 0.5); // x stores the user input in cents

    int y = x / 100000; // 1000 dollars is 100,000 cents
    printf("\nNo. of P1000 bill: %d",y);
    x = x % 100000;

    ...

    y=x / 25; // we're working with cents, so 25 = 25 cents
    printf("\nNo. of 25 cents: %d",y);    
    x = (x % 25);

    ...
}

Answer 3

Scan the user's value into a float, then separate the dollars and cents into two int values.

The coins required for the cents value should then be very easy to calculate, using the same method you've already used (except dividing/mod by 25 for 25 cents, 1 for 1 cent etc.)