NWP-Practical-7

                                                                      Practical#7
AIM: Program to convert lower-case character into upper-case character using UDP Socket.
Theory: RHS:

/************* UDP SERVER CODE *******************/

#include “stdio.h”
#include “sys/socket.h”
#include “netinet/in.h”
#include “string.h”

#include “stdlib.h”

int main()

{

  int udpSocket, nBytes;

  char buffer[1024];

  struct sockaddr_in serverAddr, clientAddr;

  struct sockaddr_storage serverStorage;

  socklen_t addr_size, client_addr_size;

  int i;

  /*Create UDP socket*/

  udpSocket = socket(PF_INET, SOCK_DGRAM, 0);

  /*Configure settings in address struct*/

  serverAddr.sin_family = AF_INET;

  serverAddr.sin_port = htons(7891);

  serverAddr.sin_addr.s_addr = inet_addr("127.0.0.1");

  memset(serverAddr.sin_zero, '\0', sizeof serverAddr.sin_zero);  

  /*Bind socket with address struct*/

  bind(udpSocket, (struct sockaddr *) &serverAddr, sizeof(serverAddr));

  /*Initialize size variable to be used later on*/

  addr_size = sizeof serverStorage;

  while(1){

/* Try to receive any incoming UDP datagram. Address and port of    requesting client will be stored on serverStorage variable */

    nBytes = recvfrom(udpSocket,buffer,1024,0,(struct sockaddr *)&serverStorage, &addr_size);

    /*Convert message received to uppercase*/

    for(i=0;i

      buffer[i] = toupper(buffer[i]);

    /*Send uppercase message back to client, using serverStorage as the address*/

    sendto(udpSocket,buffer,nBytes,0,(struct sockaddr *)&serverStorage,addr_size);

  }

  return 0;

}

/************* UDP CLIENT CODE *******************/

//#include “stdio.h”
//#include “sys/socket.h”
//#include “netinet/in.h”
//#include “string.h”
//#include “stdlib.h”

int main(){

  int clientSocket, portNum, nBytes;

  char buffer[1024];

  struct sockaddr_in serverAddr;

  socklen_t addr_size;

  /*Create UDP socket*/

  clientSocket = socket(PF_INET, SOCK_DGRAM, 0);

  /*Configure settings in address struct*/

  serverAddr.sin_family = AF_INET;

  serverAddr.sin_port = htons(7891);

  serverAddr.sin_addr.s_addr = inet_addr("127.0.0.1");

  memset(serverAddr.sin_zero, '\0', sizeof serverAddr.sin_zero);  

  /*Initialize size variable to be used later on*/

  addr_size = sizeof serverAddr;

  while(1){

    printf("Type a sentence to send to server:\n");

    fgets(buffer,1024,stdin);

    printf("You typed: %s",buffer);

    nBytes = strlen(buffer) + 1;

    /*Send message to server*/

    sendto(clientSocket,buffer,nBytes,0,(struct sockaddr *)&serverAddr,addr_size);

    /*Receive message from server*/

                nBytes = recvfrom(clientSocket,buffer,1024,0,NULL, NULL);

    printf("Received from server: %s\n",buffer);

  }

  return 0;

}

Output:LHS

Compile & Run

Firstly compile and run server socket on Terminal1.

Secondly compile and run client socket on Terminal2.

Now type string on client socket on Terminal2.

Server will send back a string uppercase.