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

EOF can be triggered through keyboard by pressing keys ctrl+d in Unix and ctrl+c in Windows.

Sample Code:

    void main()
    {
           printf(" value of getchar() != eof is %d ",(getchar() != EOF));
           printf("value of eof %d", EOF);
    }

Output:

[root@aricent prac]# ./a.out 
a
 value of  getchar() != eof is 1 value of eof -1
[root@aricent prac]# ./a.out 
Press    ctrl+d
 value of   getchar() !=  eof is 0 value of eof -1[root@aricent prac]#