binary tree of 15 processes by C program - fork

Question

How we can make a fork binary tree that gives 15 processes in C program? I tried to write the code but I have some difficulty with the 15 processes. Also, fork always confused me!
Also, For each process, we should print out its process id and the id of its parent.
this is my code:
((when I copy paste my code, I cannot post the question))
if you can help me with the right code, I would be more than happy
thank you

Answer 1

You need to keep forking. This'll spawn 15 processes for you using fork:
#include <stdlib.h>
#include <stdio.h>
int main() {
int returnPid;
int numForks = 0;
while (numForks++ < 15) {
if ((returnPid = fork()) == -1) {
perror("can't fork");
exit(1);
} else if (returnPid == 0) {
// Child process
printf("Child: returnedPid = % d, my pid = %d, parent pid = %d, fork count = %d \n", returnPid, getpid(), getppid(), numForks);
} else {
printf("Parent: returnedPid = %d, my pid = %d, parent pid = %d \n ", returnPid, getpid(), getppid(0));
exit(0);
}
}
exit(0);
}
Output:
Parent: returnedPid = 15622, my pid = 15621, parent pid = 13927
Child: returnedPid = 0, my pid = 15622, parent pid = 1, fork count = 1
Parent: returnedPid = 15623, my pid = 15622, parent pid = 1
Child: returnedPid = 0, my pid = 15623, parent pid = 1, fork count = 2
Parent: returnedPid = 15625, my pid = 15623, parent pid = 1
Child: returnedPid = 0, my pid = 15625, parent pid = 15623, fork count = 3
Parent: returnedPid = 15626, my pid = 15625, parent pid = 1
Child: returnedPid = 0, my pid = 15626, parent pid = 1, fork count = 4
Parent: returnedPid = 15627, my pid = 15626, parent pid = 1
Child: returnedPid = 0, my pid = 15627, parent pid = 15626, fork count = 5
Parent: returnedPid = 15628, my pid = 15627, parent pid = 1
Child: returnedPid = 0, my pid = 15628, parent pid = 1, fork count = 6
Parent: returnedPid = 15629, my pid = 15628, parent pid = 1
Child: returnedPid = 0, my pid = 15629, parent pid = 15628, fork count = 7
Parent: returnedPid = 15631, my pid = 15629, parent pid = 1
Child: returnedPid = 0, my pid = 15631, parent pid = 15629, fork count = 8
Parent: returnedPid = 15632, my pid = 15631, parent pid = 1
Child: returnedPid = 0, my pid = 15632, parent pid = 1, fork count = 9
Parent: returnedPid = 15634, my pid = 15632, parent pid = 1
Child: returnedPid = 0, my pid = 15634, parent pid = 15632, fork count = 10
Parent: returnedPid = 15635, my pid = 15634, parent pid = 1
Child: returnedPid = 0, my pid = 15635, parent pid = 15634, fork count = 11
Parent: returnedPid = 15636, my pid = 15635, parent pid = 1
Child: returnedPid = 0, my pid = 15636, parent pid = 15635, fork count = 12
Parent: returnedPid = 15637, my pid = 15636, parent pid = 1
Child: returnedPid = 0, my pid = 15637, parent pid = 15636, fork count = 13
Parent: returnedPid = 15638, my pid = 15637, parent pid = 1
Child: returnedPid = 0, my pid = 15638, parent pid = 15637, fork count = 14
Parent: returnedPid = 15639, my pid = 15638, parent pid = 1
Child: returnedPid = 0, my pid = 15639, parent pid = 15638, fork count = 15