client server multi-threaded script

I have to do a tcp/ip client server programming for 3 threads in C . but i am not able to understand how will i write it for 3 ports number.Plzz help.... /*******************Server program*************************/ #include<stdio.h> #include<stdlib.h> #include<string.h> #include<netinet/in.h> #include<sys/types.h> #include<sys/socket.h> #include<netdb.h> #include<unistd.h> #include<pthread.h> void error(const char *msg) //system call fails { perror(msg); exit(1); } void *My_Msg_Func(void *ptr) { char *msg; int i = 0; msg = (char *)ptr; while(i < 10) { sleep(10); printf("%s\n",msg); ++i; } return NULL; } int main(int argc , char *argv[]) { int socketfd; int newsocketfd; int portno; int cliLen; //size of address of client char array[10] = "Welcome"; //read server characters from socket connection struct sockaddr_in server_addr; struct sockaddr_in client_addr; int value; pthread_t thread_array[3]; int i; int thread_num = 3; int ret; char *msg = "THREAD"; if(argc < 2) { fprintf(stderr,"ERROR,no port provided"); exit(1); } /*Create Socket*/ socketfd = socket(AF_INET,SOCK_STREAM,IPPROTO_TCP); if(socketfd < 0) { error("ERROR in opening socket"); exit(1); } bzero((char*)&server_addr , sizeof(server_addr)); portno = atoi(argv[1]); server_addr.sin_family = AF_INET; server_addr.sin_port = htons(portno); // memcpy(&server_addr.sin_addr.s_addr ,host->h_addr ,host->h_length); server_addr.sin_addr.s_addr = 0; /*Binding Socket*/ if( bind( socketfd ,(struct sockaddr*)&server_addr ,sizeof(server_addr)) < 0) { error("ERROR in binding : Unable to bind"); exit(1); } if((listen(socketfd ,5)) < 0) { error("ERROR in listening"); exit(1); } printf("\n TCP server is waiting for client\n"); fflush(stdout); while(1) { cliLen = sizeof(client_addr); /*Accept a connection by server*/ newsocketfd = accept( socketfd ,(struct sockaddr*)&client_addr ,&cliLen); if(newsocketfd < 0) { error("ERROR on accepting"); } printf("Connection is established\n"); //printf("Connection established from %s %d \n",inet_ntoa(client_addr.sin_addr),ntohs(client_addr.sin_port)); for(i = 0; i < thread_num; i++) { if((ret = pthread_create(&thread_array[i],NULL,My_Msg_Func,(void *)msg )) < 0) { printf("Thread creation is failed at %d",ret); exit(1); } printf("Thread is created\n"); value = send(newsocketfd ,array ,sizeof(array),0); if(value < 0) { error("ERROR sending to socket"); } printf("Message sended successfully\n"); printf("message is %s\n",array); value = recv(newsocketfd ,array ,sizeof(array) ,0); if(value < 0) { error("ERROR in receiving to socket"); } printf("Message received successfully\n"); printf("message is %s\n",array); } for(i = 0; i < thread_num; i++) { pthread_join(thread_array[i], NULL); } } /*Closing connections*/ close(newsocketfd); close(socketfd); return 0; } /***************Client program***************/ #include<stdio.h> #include<stdlib.h> #include<string.h> #include<sys/types.h> #include<sys/socket.h> #include<netinet/in.h> #include<netdb.h> void error(char *msg) { perror(msg); exit(0); } int main(int argc ,char *argv[]) { int socketfd; int portno; struct sockaddr_in server_addr; struct hostent *server; char array[10]; int value; if(argc < 3) { fprintf(stderr," %s hostname port ",argv[0]); exit(0); } portno = atoi(argv[2]); /* Opening Socket */ socketfd = socket(AF_INET ,SOCK_STREAM ,IPPROTO_TCP); if(socketfd < 0) { error("ERROR in opening socket"); } server = gethostbyname(argv[1]); // arg[1] contains host name if(server == NULL) { fprintf(stderr," ERROR, no host available"); exit(0); } bzero((char *)&server_addr ,sizeof(server_addr)); // set buffer value zero server_addr.sin_family = AF_INET; bcopy((char *)server->h_addr ,(char *)&server_addr.sin_addr.s_addr ,server->h_length); // copy length bytes of character string server_addr.sin_port = htons(portno); /* connect function called by client to establish connection to server */ if(connect(socketfd ,(struct sockaddr *)&server_addr ,sizeof(server_addr)) < 0) { error("ERROR in connection"); } bzero(array,10); fgets(array,9,stdin); value = send(socketfd ,array ,sizeof(array) ,0); if(value < 0) { error("ERROR in sending to socket"); } value = recv(socketfd ,array ,sizeof(array),0); if(value < 0) { error("ERROR receiving from socket"); } printf("%s\n",array); close(socketfd); return 0; } here program is working for 1 port no. but i do not know how to do it for 3 different port numbers...can some one plzz modify the server program for the port numbers suppose 5000,6000,7000....? plzz solve it ....