#include <stdio.h>
#include <stdlib.h>
#include <sys/wait.h>

int main(){
  int fd[2], pid1, pid2;
  char *my_program1[3] = {“/bin/ls”, “-l”, NULL};   #directory listing
  char *my_program2[2] = {“/usr/bin/wc”, NULL};     #line, word and character count

  pipe(fd);
  if ((pid1=fork())==0){
    close(1);   # close the stdout
    dup(fd[1]);     # duplicate fd[1] to position 1
    close(fd[0]);
    close(fd[1]);
    execv(my_program1[0],my_program1); # the output of the program redirected to fd[1]
  }
if ((pid2=fork())==0){
    close(0);    #close the stdin
    dup(fd[0]);  #duplicate the fd[0] to position 0
    close(fd[0]);
    close(fd[1]);
    execv(my_program2[0],my_program2); # the input of the program redirected to fd[1]
  }

 close(fd[0]);
 close(fd[1]);
 waitpid(pid1, NULL, 0);
 waitpid(pid2, NULL, 0);
 return 0;
}