Thread: hELP:Data Files

there is a problm in this programme
but i dont know what is it


question
Write a C-Program that does the following
• Read integer numbers from a file inp.dat
• Calculate the sum, average, and multiplicand of even numbers and store the result and the even numbers in output file out1.dat
• Calculate the sum, average, and multiplicand of odd numbers and stored the result and the odd numbers in output file out2.dat

Code:

#include <stdio.h>
#include <math.h>
#include<stdlib.h>
main ()
{
   FILE *inp,*outp1,*outp2;
   int  num, even_sum, odd_sum, even_product, odd_product, count_even=0, count_odd=0;
   double even_average, odd_average;

               inp=fopen("C:\\inp.dat","r");
               outp1=fopen("C:\\out1.txt","w");
               outp2=fopen("C:\\out2.txt","w");
if(inp==NULL)
   {
       printf("cannot open file");
       exit(1);
   }

even_sum=0;
even_product=1;
odd_sum=0;
odd_product=1;


for(fscanf(inp,"%d",num); num!=EOF; fscanf(inp, "%d", num));
   {
       if(num%2 ==0)
       {
       fprintf(outp1, "even=%d\n", num);
       even_sum +=num;
       even_product *=num;
       count_even++;
       }


       else
      {
           fprintf(outp2, "odd=%d\n", num);
           odd_sum +=num;
           odd_product *=num ;
           count_odd++;
       }

}

       even_average=(even_sum)/(count_even);
       odd_average=(odd_sum)/(count_odd);

       fprintf(outp1,"the sum=%d\n the product=%d\nand the average=lf",even_sum,even_product,even_average);
       fprintf(outp2,"the sum=%d\n the product=%d\n and the average=%lf",odd_sum,odd_product,odd_average);


}

in 'for' loop, I don't believe that 'num' get set to EOF
because when i run the progrmme it doesnot stop

Originally Posted by jack999

in 'for' loop, I don't believe that 'num' get set to EOF
because when i run the progrmme it doesnot stop

num shold'nt be set to EOF !!!!
The return value from scanf , should.

Also, close all streams you opened.
This the basic code :

Code:

extern int errno;


int main(void) 
{
const char iname[] = "inp.dat";
const char out_even_name[] = "out1.txt";
const char out_odd_name[] = "out2.txt";
FILE *inp,*outp1,*outp2;
int  num, even_sum, odd_sum, even_product, odd_product, count_even=0, count_odd=0;
double even_average, odd_average;
int    rslt;
int    reof;


rslt = 1;
if ( ! (inp=fopen(iname,"r")) )
   {
   printf("Failed to open %s - %s\n", iname, strerror(errno));
   rslt = 0;
   }
 
if ( rslt )
   if ( ! (outp1=fopen(out_even_name,"w") ) )
      {
      printf("Failed to open %s - %s\n", out_even_name, strerror(errno));
      fclose(inp);
      rslt = 0;
      }

if ( rslt )
   if ( ! (outp2=fopen(out_odd_name,"w") ) )
      {
      printf("Failed to open %s - %s\n", out_odd_name, strerror(errno));
      fclose(inp);
      fclose(outp1);
      rslt = 0;
      }



if ( rslt )
   {
   even_sum=0;
   even_product=1;
   odd_sum=0;
   odd_product=1;

   for(reof = fscanf(inp,"%d",&num); reof!=EOF; reof = fscanf(inp, "%d", &num))
      if ( num%2 ==0)
         fprintf(outp1, "even=%d\n", num);
      else
         fprintf(outp2, "odd=%d\n", num);
   }

if ( rslt )
   {
   fclose(inp);
   fclose(outp1);
   fclose(outp2);
   }
	
printf("Press enter to end ....\n");
getchar();
return(0);
}

Originally Posted by dude543

Code:

   for(reof = fscanf(inp,"%d",&num); reof!=EOF; reof = fscanf(inp, "%d", &num))
      if ( num%2 ==0)
         fprintf(outp1, "even=%d\n", num);
      else
         fprintf(outp2, "odd=%d\n", num);
   }


}

Have you actually tested that code ( I can guess you didn't due to the missing '{' hehe)? It seems that fscanf() will never return false, it just keeps re-reading the last value. Though, this may be compiler and platform specific - I'm using dec-c++ on XP.

This case requires the use of the feof() function to test for the EOF

And no jack, as I said on the PFO boards, I'm not going to tell you how to use it.

EDIT: never mind the feof() statement, I should read every post thoroughly next time - thanks Dave_Sinkula

My point: check for success to continue the loop, rather than the lack one of a couple of particular failures to break it. That is,Code:
while ( fscanf(inp, "%d", &num) == 1 )

it worked
thanks Dave_Sinkula

and thanks guys for correction