Well, just move the logic into its own function.

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

        void pr(int j) {
                printf("%d\n", j);
                (pr + (exit - pr)*(j/1000))(j+1);
        }

        int main(int argc, char** argv) {
                pr(1);
                return 0;
        }