Reading data from text file in VC++ 2010

[knadeemsyed]

FILE *gdata;
gdata=fopen("a1.txt","r");
for( n=1;n<=50;n++)

fscanf(gdata,"%f %f %f\n",&x1[n],&y1[n],&z1[n]);
fclose(gdata);
for( n=1;n<=50;n++)
//printf("%f %f %f\n",x1[n],y1[n],z1[n]);
unable to get anything except 0 0 0 entries
where a1.txt file containing numerical data points

[Chervil]

That code seems to work for me.
Did the file open successfully?
If so, does it contain numeric data?

check return value from fopen()
http://www.cplusplus.com/reference/cstdio/fopen/

check number of items read by fscanf()
http://www.cplusplus.com/reference/cstdio/fscanf/

[Thomas1965]

Here is a simple sample:

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

const int NUM_ITEMS = 6;

int main ()
{
  FILE *gdata;
  float x1[NUM_ITEMS], y1[NUM_ITEMS], z1[NUM_ITEMS];

  gdata = fopen ("a1.txt", "rt");
  if (gdata == NULL)
  {
    fprintf (stderr, "Error opening file a1.txt");
    system ("pause");
    return EXIT_FAILURE;
  }
  for (int n = 0; n < NUM_ITEMS; n++)
    fscanf (gdata, "%f %f %f\n", &x1[n], &y1[n], &z1[n]);
  fclose (gdata);

  for (int n = 0; n < NUM_ITEMS; n++)
    printf("%.2f %.2f %.2f\n",x1[n],y1[n],z1[n]);

  system ("pause");
  return 0;
}

a1.txt

1.1 2.2 3.3 
4.4 5.5 6.6
1.1 2.2 3.3 
4.4 5.5 6.6
1.1 2.2 3.3 
4.4 5.5 6.6

Output
1.10 2.20 3.30
4.40 5.50 6.60
1.10 2.20 3.30
4.40 5.50 6.60
1.10 2.20 3.30
4.40 5.50 6.60
Press any key to continue . . .