TCP Client

#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <unistd.h>

#define DEFAULT_BUFLEN 512
#define DEFAULT_PORT 27015

unsigned int sleep(unsigned int seconds);

int Meni1() {
	int op;
	system("clear");
	printf("1.) Registruj se\n");
	printf("2.) Loginuj se\n");
	printf("Izaberite opciju: ");
	scanf("%d", &op);

	return op;
}

int Meni2() {
	int op;
	system("clear");
	printf("1.) Upload datoteku na server \n");
	printf("2.) Download datoteku sa servera \n");
	printf("3.) Prikazi listu datoteka \n");
	printf("4.) Odjava sa servera \n");
	printf("Izaberite opciju: ");
	scanf("%d", &op);

	return op;
}

int main(int argc , char *argv[])
{
    int sock;
    struct sockaddr_in server;
    char message[10];
    ///////////////
	char username[DEFAULT_BUFLEN];
	char password[10];
	int opcija;
	int flagreg = -1;
	int flaglog = -1;

    //Create socket
    sock = socket(AF_INET , SOCK_STREAM , 0);
    if (sock == -1)
    {
        printf("Could not create socket");
    }
    puts("Socket created");

    server.sin_addr.s_addr = inet_addr("10.81.30.45");
    server.sin_family = AF_INET;
    server.sin_port = htons(DEFAULT_PORT);

    //Connect to remote server
    if (connect(sock , (struct sockaddr *)&server , sizeof(server)) < 0)
    {
        perror("connect failed. Error");
        return 1;
    }
    puts("Connected\n");

    while(1) {

		opcija = Meni1();
		send(sock, &opcija, sizeof(opcija), 0);
		switch(opcija) {
			case 1 :
				system("clear");
				printf("* Registracija *\n");
				printf("Unesite username: ");
				scanf("%s", username);
				if(send(sock, username, strlen(username), 0) < 0) {
					printf("Klijent: neuspesno slanje");
					return 1;
				}
				printf("Unesite password: ");
				scanf("%s", password);
				if(send(sock, password, strlen(password), 0) < 0) {
					printf("Klijent: neuspesno slanje");
					return 1;
				}
				recv(sock, &flagreg, sizeof(flagreg), 0);
				printf("Flagreg : %d\n", flagreg);
				break;
			case 2 :
				system("clear");
				printf("* Login *\n");
				printf("Unesite username: ");
				scanf("%s", username);
				if(send(sock, username, strlen(username), 0) < 0) {
					printf("Klijent: neuspesno slanje");
					return 1;
				}
				printf("Unesite password: ");
				scanf("%s", password);
				if(send(sock, password, strlen(password), 0) < 0) {
					printf("Klijent: neuspesno slanje");
					return 1;
				}
				recv(sock, &flaglog, sizeof(flaglog), 0);
				printf("Flagreg : %d\n", flaglog);
				break;
			default :
				printf("Pogresna opcija\n");
				sleep(1);
				break;
		}
		sleep(3);
		system("clear");
		if(flagreg == 0)
			break;
		else if(flaglog == 0)
			break;
	}

    while(1) {

		opcija = Meni2();
		send(sock, &opcija, sizeof(opcija), 0);
		switch(opcija) {
			case 1 :
				system("clear");
				printf("Upload\n");
				sleep(2);
				break;
			case 2 :
				system("clear");
				printf("Download\n");
				sleep(2);
				break;
			case 3 :
				system("clear");
				printf("Listanje datoteka\n");
				sleep(2);
				break;
			case 4 :
				system("clear");
				printf("Uspesno ste odjavljeni sa servera\n");
				sleep(1);
				break;
			default :
				printf("Pogresna opcija\n");
				sleep(1);
				break;
		}
		if(opcija == 4)
			break;
	}

    close(sock);

    return 0;
}