first of all i would like to ask you how to create this process tree listed below with using only fork() function.
|____1____
|___2__ |
|_4_ | |_3_
| | | | |
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
int main() {
if (fork()) {
The thing is I don't know what to do next and how it works.