Check a Number in parent process and pass result to Child Process

#include<stdio.h>
#include<unistd.h>


main()
{
int fd[2],f,i,num,flag=1;pipe(fd);
f=fork();
if(f>0)
{
printf("PARENT PROCESS..");
printf("\nEnter a number : ");
scanf("%d",&num);


if(num==1)flag=0;for(i=2;i<=(num/2);i++)
if(num%i==0)
{
flag=0;
break;
}
close(fd[0]);
write(fd[1],&flag,sizeof(flag));


}
else if (f==0)
{
printf("\n\nCHILD PROCESS.");close(fd[1]);
read(fd[0],&flag,sizeof(flag));
if(flag==1)printf(" \n\tIt is a prime number..\n");
else printf("\n\t It is not a prime number..\n");
}


}

Posted in: UNIX PROGRAMS