chatClient.cpp

// Client side implementation of UDP client-server model
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <iostream>
#include <thread>
#define PORT	8080
#define MAXLINE 1024
struct sockaddr_in	 servaddr;
void chatInput(int sockfd){
    while(1){
        char buffer[MAXLINE];
        sockaddr servaddr;
        socklen_t len;
        int n = recvfrom(sockfd, (char *)buffer, MAXLINE, MSG_WAITALL, (struct sockaddr *) &servaddr, &len);
        buffer[n] = '\0';
        if(!strcmp(buffer,"@")){
            printf("you have left the room\n");
            break;
        }
        printf("%s\n", buffer);
    }
}

void chatOutput(int sockfd, char clientName[MAXLINE]){
    while(1){
        char clientMsg[MAXLINE]="";
        char msg[MAXLINE];
        strcpy(msg,clientName);
        scanf("%[^\n]s", &clientMsg);
        getchar();
        if(!strcmp(clientMsg,"LEAVE ROOM")){
            strcat(msg," &");    
            sendto(sockfd, (const char *)msg, strlen(msg),
            MSG_CONFIRM, (const struct sockaddr *) &servaddr,
                sizeof(servaddr));
            break;
        }
        printf("You: %s\n", clientMsg);
        strcpy(msg,clientName);
        strcat(msg,": ");
        strcat(msg,clientMsg);
        sendto(sockfd, (const char *)msg, strlen(msg),
            MSG_CONFIRM, (const struct sockaddr *) &servaddr,
                sizeof(servaddr));
    }
}

// Driver code
int main() {
	int sockfd;
	char clientName[MAXLINE];
    socklen_t len;

	// Creating socket file descriptor
	if ( (sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0 ) {
		perror("socket creation failed");
		exit(EXIT_FAILURE);
	}

	memset(&servaddr, 0, sizeof(servaddr));
	
	// Filling server information
	servaddr.sin_family = AF_INET;
	servaddr.sin_port = htons(PORT);
	servaddr.sin_addr.s_addr = INADDR_ANY;
	
    printf("Please enter your name: ");
    scanf("%[^\n]s", clientName);
    getchar();
    printf("welcome to the room!\n");
    char joinMsg[MAXLINE];
    strcpy(joinMsg,clientName);
    strcat(joinMsg," has joined!");
    strcat(joinMsg,"@");
    sendto(sockfd, (const char *)joinMsg, strlen(joinMsg),
            MSG_CONFIRM, (const struct sockaddr *) &servaddr,
                sizeof(servaddr));

    std::thread thInp(chatInput, sockfd);
    std::thread thOut(chatOutput, sockfd, clientName);
    thInp.join();
    thOut.join();
	close(sockfd);
	return 0;
}
//g++ -std=c++11 chatClient.cpp -lpthread -o chatClient