How to create a file on system drive on windows 8.1 in c?

Take a look at the code below, it works for drive d but not for c (system drive) - I guess it's because of some security restrictions but how to bypass them?

#include <stdio.h>

main()
{
   FILE *fp;

   fp = fopen("c:\\test.txt", "w+");
   fprintf(fp, "This is testing for fprintf...\n");
   fputs("This is testing for fputs...\n", fp);
   fclose(fp);
}