Why can't I find the value of EOF in C?

Question

I\'m reading the book \"The C Programming Language\" and there is an exercise that asked to verify that the expression getchar() != EOF is returning 1 or 0. Now

Answer 1

To display the value of EOF

#include 
int main()
{
   printf("EOF on my system is %d\n", EOF);
   return 0;
}

EOF is defined in stdio.h normally as -1