Question regarding array for printing income and tax on to a file

**Detrigan** · 11-03-2003

Hey guys,
I'm stuck on a tax program. First i need to use a loop to generate 10 incomes and save them in an array. Then use a loop to calculate the tax and save the taxes in another array. After calculating all the taxes, i have to write the output to a file.
This is what i have so far... (I got it to run but i dont know how to loop the scanf)

Code:

#include <stdio.h>
#include <math.h>
void main (void)

{

	int i, j, k, num_elem;
	double   tax, x[9], y[9], z[9];
	FILE *outfile;
	
	printf ("Type in your ten incomes\n");
	
	outfile= fopen("a6q1.out","w");
	
	scanf ("%lf", &x[0]);
	
	fprintf (outfile, "Value of EOF = %d\n", EOF);
	
	
	while (x[i] != EOF) i++;

	
	num_elem = i;
	
	fprintf(outfile,"x[i]\n");

	for (j=0; j<num_elem; j++)
		{
			if(x[j]<1000)
			{
			tax=0;
			printf("%.2lf %.2f", x[j], tax);
			}
			else if(x[j]>=2000)
			{
			tax=x[j]*0.30;
			printf("%.2lf %.2f", x[j], tax);
			}
			else 
			{
			tax=x[j]*0.20;
			printf("%.2lf %.2f", x[j], tax);
			}
		}
		
	fclose(outfile);
}

Any help would be greatly appreciated. Thanks!

**Prelude** · 11-03-2003

>void main (void)
You really don't want to see me have a conniption, do you? void main is the root of all evil, use

Code:

int main ( void )

instead. No argument, do it.

Concerning your code...have you tried following the logic on paper? Did you become as confused as I did? Try something more like this:

Code:

#include <stdio.h>

#define N    10
#define HTAX 0.30
#define LTAX 0.20
#define LOW  1000
#define HIGH 2000

int main ( void )
{
  double income[N];
  double taxes[N];
  double taxed_income[N];
  int i;
  int j;

  printf ( "Enter %d incomes: ", N );
  fflush ( stdout );
  for ( i = 0; i < N && scanf ( "%lf", income[i] ) == 1; i++ ) {
    if ( income[i] < LOW )
      taxes[i] = 0;
    else if ( income[i] >= HIGH )
      taxes[i] = income[i] * HTAX;
    else
      taxes[i] = income[i] * LTAX;
    taxed_income[i] = income[i] + taxes[i];
  }
  for ( j = 0; j < i; j++ )
    printf ( "%d: %f\n", j, taxed_income[j] );

  return 0;
}

Of course, this doesn't print to file.

**Detrigan** · 11-03-2003

Thanks so much, but i still need to print to file... I will keep trying.

**Prelude** · 11-03-2003

>but i still need to print to file...
I know, I did that on purpose because I'm evil.

>I will keep trying.
The trick to working successfully with files is to remember that once they're open, you can use them exactly the same way as stdin/stdout, just use functions that take a stream pointer instead of assuming stdin or stdout like scanf and printf do. And don't forget to close your file when you're done.

I wrote a FAQ entry concerning this topic if you're interested in more detail. Of course, I wrote it a while ago and haven't read it in some time, so read at your own risk...I've been known to make mistakes.

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