Question

2. Read in an unknown number of real values from a file called “data.txt”. Calculate the average of the real numbers. Output the average of the real numbers to a file called “output.txt”. Some skeleton code is provided for you below.

#include

  

int main (void)

{

                        FILE *infile = NULL;

                        FILE *outfile = NULL;

                        /* Fill in the code to open a file. Make sure you check that the file was open successfully. */

                        while (!feof (infile))

                        {

                                    /* Read in the real values. */

                                    /* Keep track of the number of values read and the sum of the values. */

                        }

                        /* Output average to a file named "output.txt". */

                        /* Close your files. */

                        return 0;

}

Write code in C

Answer 1

#include <stdio.h>
#include<stdlib.h>
int main()
{
   double i,sum,avg;
   int count=0;

   FILE *infile = NULL;
   FILE *outfile = NULL;

   infile = fopen("data.txt", "r"); /* openig file in read mode */

   /* checking that the file was open successfully or not */
   if(infile==NULL)
   {
       printf("Error in opening data.txt file\n");
       exit(1);
   }

   // read 1st number
   fscanf (infile, "%lf", &i);

   sum = 0.0;

   // continuously read all number
   while (!feof (infile))
    {
        count++; /* count total number of real value are present*/

        /* sum of the values. */
        sum += i ;

         fscanf (infile, "%lf", &i);
        
        
    }

    avg = sum/count; /* calculate average */

    outfile = fopen("output.txt", "w"); /* opening output file in write mode */

    /* checking that the file was open successfully or not */
   if(outfile==NULL)
   {
       printf("Error in opening output.txt file\n");
       exit(2);
   }

   fprintf(outfile,"%lf ",avg); /*wrire average to output file*/

   fclose(infile); /* closing input file */
   fclose(outfile); /* closing output file */
    
  
   return 0;
}