Question

Using pipes for inter-process communications, write a C program to produce a parent/child relationship in which the parent process repeatedly counts and displays on the screen the number of characters for any user password the child process inputs to the pipe. The communications should cease once the string “Done” is inputted.

Answer 1

This is a C program to produce a parent/child relationship in which

the parent process repeatedly counts and displays on the screen the number of characters for any user password the child process inputs to the pipe.

The communications will cease once the string “Done” is inputted.

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

int main()
 {
   int pipefds[2];
   int returnstatus;
   int pid;
   char password[100];
   returnstatus = pipe(pipefds);
   if (returnstatus == -1) {
      printf("Unable to create pipe\n");
      return 1;
   }
   pid = fork();
   while(1)
   {   printf("enter the password");
       scanf("%s" , password);
       if(password="Done")
       { return 0;}
       else
      {    // child process
           if (pid == 0) {
             printf("child Process - Writing to pipe - password is %s\n", password);         
             write(pipefds[1], password, sizeof(password));}
           else { //parent process
             read(pipefds[0], readmessage, sizeof(readmessage)); 
             printf("Child Process - Reading from pipe – length of password is %d\n", strlen(readmessage));}
  }

return 0;

}