How to obtain the length of a file

I am trying to run a simple C program that takes a file of random floating point values, automatically identify the length of the file and use the length to perform further computation. However, my compiler either hangs or I get erroneous results. Here is my code

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <math.h>



int main()
{

    
   FILE *fptr;
    int count = 0; // Line counter (result)
    char ch; // To store a character read from file

    if ((fptr = fopen("C:\\Users\\Evandovich\\Desktop\\White_Noise.txt","r")) == NULL){
       printf("Error! opening file");

       // Program exits if the file pointer returns NULL.
       exit(1);
   }

    // Extract characters from file and store in character ch
    for (ch = getc(fptr); ch != EOF; ch = getc(fptr))
    {
        if (ch == '\n') // Increment count if this character is newline
            count = count + 1;
    }
      printf("The file has %d lines\n ", count);

// use the value of "count" to be the length of the array.

  char arrayNum[count];
  char *eptr;
  double result, result1[count];


  for (int i = 0; i<count; i++)
   {
       fscanf(fptr,"%s", &arrayNum[i]);

       /* Convert the provided value to a double */
    result = strtod(&arrayNum[i], &eptr);
    result1[i] = pow(result,2) ;
    printf("value %f\n", result1[i]);

   }


   fclose(fptr);
    return 0;
}

What particularly is the error? Your input is well appreciated

INPUT file (N.txt) contains

0.137726
0.390126
-0.883234
0.006154
-0.170388
-1.651212
0.510328

OUTPUT The file has 7 files

value 0.000000
value 0.000000
value 0.000000
value 0.000000
value 0.000000
value 0.000000
value 0.000000

Expected The file has 7 files

value 0.018968
value 0.152198
value 0.780102
value 0.000038
value 0.029032
value 2.726501
value 0.260435