C program demonstrating fork parent-child

#include <stdio.h>
#include <unistd.h>
#include <sys/wait.h>
int main(){
 pid_t p = fork();
 if(p < 0){ perror("fork"); return 1; }
 else if(p == 0){
   // Child
   printf("Child: PID=%d, PPID=%d
", getpid(), getppid());
   // child work
 } else {
   // Parent
   printf("Parent: PID=%d, Child PID=%d
", getpid(), p);
   wait(NULL); // wait for child
   printf("Parent: child finished
");
 }
 return 0;
}

Explanation: fork() duplicates process; returns 0 in child, child PID in parent, -1 on error. Parent and child execute concurrently with separate address spaces. wait() synchronizes. Demonstrates that after fork, both continue after fork statement.