#include <sys/wait.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <errno.h>

extern int errno;

int *arg[] = {"printf","scanf",(int *)0};
#define NULL	0

int main (void) 
{

	
if (fork()) 	 			/*This is the child process */
	{
	sleep(1);
	execv("/home/Desktop/Sum",arg);	/*Execute the child process*/
	 /*	exit (0);			Should never get
here,terminate */
	 }
	 
/* parent code */
else
	{
	printf ("Parent in execution …\n");
	sleep(2);
	
	if (wait (NULL) > 0)	/*child terminating */
	printf ("Parent detects terminating child\n");
	
	sleep(2);
	}
	printf ("Parent terminating… \n");	
}

Sum.c

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <errno.h>

extern int errno;

printf("Enter the number for summation = ");
scanf("%d",&num);	
	printf("The number entered is = %d\n", num);
while(num<2)
	{
	printf("Error. The value must greater than 1\n");
	printf("Enter the number for summation = ");		
	scanf("%d",&num);
	printf("The number entered is = %d\n", num);
	}
	
	for(i=1;i<=num;i++)
	{
	sum = sum + i;
	}

/* sum.c */
#include <stdio.h>
#include <stdlib.h>

int main()
{
    int num;

    printf("\nEnter a non-negative integer: ");
    if ((scanf("%d", &num) == 1)  && (num >= 0)){
        printf("The sum of integers from 0 up to and including %d is ", num);
        num *= (num + 1);
        num /= 2;
        printf("%d\n\n", num);
        return (EXIT_SUCCESS);
    }
    else {
        printf("That was an invalid entry\n\n");
        return (EXIT_FAILURE);
    }
}

/* z.c: the main forking program */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <wait.h>

int main(int argc, char **argv)
{
    char *target = "/tmp/sum"; /* the default argument              */
    char *arg[] = {"sum", 0};  /* null-terminated list of arguments */
    int status;

    if (argc > 1) {
        target = argv[1];
    }

    if (fork() == 0) { /* This is the forked child process */
        execv(target, arg); /* Execute the target process */
        perror(target);    /* It shouldn't return */
        exit(EXIT_FAILURE);
    }

    else { /* This is the parent process */
        int retval;
        retval = wait(&status);
        if (retval == -1) {
            perror("Uh-oh");
        }
        else {
            if (status == EXIT_SUCCESS) {
                printf("Satisfactory result from %s\n", target);
            }
            else {
                printf("Unsatisfactory result from %s\n", target);
            }
        }
    }
    return status;
}

#include <sys/wait.h>
#define NULL	0

int main (void) {
	/* if (____________________) {		This is the child process */
	/*    ____________________;		Execute the child process */
	/*	exit (0);				Should never get here, terminate */
/*} */

/* parent code */
	printf (“Parent in execution …\n”);
	sleep (2);
	if (wait (NULL) > 0))	/*child terminating */
printf (“Parent detects terminating child\n”);
	printf (“Parent terminating… \n”);
}

int main (void) {
printf (“Child in execution… \n”);
sleep (1);
printf (“Child terminating… \n”);
}

int main(int argc, char *argv[])

int main(int argc, char **argv)

char *target = "./test";
char *arg[3] = {"./test",            /* The name of the child program       */
                "argument_number_1", /* The command-line argument to target */
                NULL                 /* a NULL after the last argument      */
               };
.
.
.
        execv(target, arg);
.
.
.

char *target = "./test";
char *arg[2] = {"./test",            /* The name of the child program       */
                NULL                 /* No command-line arguments           */
               };
.
.
.
        execv(target, arg);
.
.

char *target = "./test";
char *arg[1] = {NULL};
.
.
.
        execv(target, arg);
.
.
.