how to identify Sever and client in a given code

Question

#include <header.h>
int copy (char *srcm char *dst) { /* procedure to copy file using the server */
struct message m1 ; /* message buffer */
long position ; /* current file position */
long client =110; /* client’s address */
initialize () ; /* prepare for execution */
position = 0 ;
do { /* Get a block of data from the source file */
m1.opcode = READ ; /* operation is read */
m1.offset = position ; /* current position in the file */
m1.count = BUF_SIZE ; /* how many bytes to read */
strcpy(&m1.name, src) ; /* copy name of file to be read to message */
send (FILE_SERVER, &m1) ; /* send the message to the file server */

receive (client, &m1) ; /* block waiting for the reply */

 

#include <header.h>
void main(int argc, char **argv) {
struct message m1, m2 ; /* incoming and outgoing messages */
int r ; /* result code */
while (1) { /* server runs forever */
receive (FILE_SERVER, &m1) ; /* block waiting for a request */
switch (m1.opcode) { /* dispatch on type of request */
case CREATE : r = do_create(&m1, &m2) ; break ;
case READ : r = do_read(&m1, &m2) ; break ;
case WRITE : r = do_write (&m1, &m2) ; break ;
case DELETE : r = do_delete (&m1, &m2) ; break ;
default : r = E_BAD_OPCODE ;
}
m2.result = r ; /* return result to client */
send (m1.source, &m2) ; /* send reply */
}};