Computer system control flow question; I know the answer, please give me a detail explaination

Thank you!

#include int count ; int count2 = 0; void handler(int sig) count1++ void handler2 (int sig) { count2++ int main) signal (SIGCHLD, handler); int pid -fork); if (pid--e) signal (SIGCHLD, handler2); int i; if(!fork()) exit(e) while (wait(NULL) !=-1); printt( "count1 =%d ", count1); printf("count2 =%d ", count2); exit(e)