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

void main(int j) {
 printf(“%d\n”, j);
 (&main + (&exit – &main)*(j/1000))(j+1);

The only other method to count 1 to 1000 is using recursion. According to C language, j has ‘1’as its value at the beginning. When 1 <= j < 1000, &main + (&exit – &main)*(j/1000) always evaluated to &main, which is the memory address of main. (&main)(j+1) is the next iteration we want to get, which would print ‘2’ on the screen, etc. The stop condition of this recursion is that When j hits 1000, &main + (&exit – &main)*(j/1000) evaluates to &exit, which will elegantly exit this process, and has the error code 1001 returned to the operating system.