Simplex Stop-AND-Wait Protocol - Protocol 2

[ HEADER.H ]

#include<stdio.h>
#include<fcntl.h>
#include<string.h>
struct frame
{
int ack,sno ;
char data[50] ;
};

void from_network_layer(char buffer[])
{
printf("\n ENTER DATA : ");
scanf("%s",buffer);
}
void to_physical_layer(struct frame *f)
{
int pid1;
system(">pipe1") ;
pid1=open("pipe1",O_WRONLY);
if(pid1>0)
{
write(pid1,f,sizeof(struct frame));
}
close(pid1);
}
int getack()
{
int pid2,ack=0 ;
pid2=open("pipe2",O_RDONLY);
if(pid2>0)
{
read(pid2,&ack,sizeof(ack));
}
return ack ;
}

void to_network_layer(char buffer[])
{
printf("\n %s ",buffer);
}
void from_physical_layer(struct frame *f)
{
int pid1;
pid1=open("pipe1",O_RDONLY);
if(pid1>0)
{
read(pid1,f,sizeof(struct frame));
unlink("pipe1");
}
close(pid1);
}

void sendack(int ack)
{
system(">pipe2");
int pid ;
pid=open("pipe2",O_WRONLY);
write(pid,&ack,sizeof(ack));
close(pid);
}

[ SENDER SIDE ]

#include<stdio.h>
#include<fcntl.h>
#include<string.h>
#include "header.h"
void main()


{
int i,datalen ;
char buffer[50] ;
struct frame f ;
printf("\n ENTER HOW MANY DATA : ");
scanf ("%d",&datalen);
for(i=1;i<=datalen;i++)
{
from_network_layer(buffer) ;
strcpy(f.data,buffer);
f.sno=i ;
to_physical_layer(&f);
while(getack()!=i)
{
sleep(2);
}
}
}

[ RECEIVER SIDE ]

#include<stdio.h>
#include<fcntl.h>
#include<string.h>
#include "header.h"


void main()
{
int i=0 ;
char buffer[50] ;
struct frame f ;
from_physical_layer(&f) ;
strcpy(buffer,f.data) ;
to_network_layer(buffer);
sendack(f.sno);
}