9bparent.c

//parent program
#include <stdio.h>
#include <sys/shm.h>
#include <sys/ipc.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>

typedef struct {
	int n;
	int arr[100];
} pack_t;

int main() {
	key_t key = 1234;
	int shmid = shmget(key, sizeof(pack_t), 0666 | IPC_CREAT);
	pack_t* shm_ptr = (pack_t*) shmat(shmid, NULL, 0666);
	printf("[PARENT] Created shared memory with key = %d, id = %d, address = %p\n", key, shmid, shm_ptr);
	printf("[PARENT] Enter n: ");
	scanf("%d", &shm_ptr->n);
	pid_t child_pid;
	if ((child_pid = fork()) == 0) {
		execlp("./child", "./child", NULL); // Child
	} else {
		wait(NULL);
		printf("[PARENT] Child finished executing.\n");
		printf("[PARENT] The first %d odd numbers are: \n", shm_ptr->n);
		for (int i = 0; i < shm_ptr->n; i++)
			printf("%d ", shm_ptr->arr[i]);
		putchar('\n');
	}

	shmdt((void*) shm_ptr);
	shmctl(shmid, IPC_RMID, NULL); // Delete shared memory
	printf("[PARENT] Shared Memory Deleted\n");
	return 0;
}