180 lines
4.4 KiB
C++
180 lines
4.4 KiB
C++
#include <iostream>
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#include <sstream>
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#include <string>
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#include <cstring>
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#include <cstdlib>
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#include <ctime>
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#include <unistd.h>
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#include <sys/socket.h>
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#include <sys/types.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#define BUFFER_SIZE 256
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#define NOPORT_RET 10
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#define INVALID_PORT_RET 20
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#define BINDERR_RET 30
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#define LISTENERR_RET 35
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using namespace std;
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class Game {
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private:
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int upper;
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int lower;
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int count;
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int answer;
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public:
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Game(void) {
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this->reset();
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}
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int get_upper() {
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return this->upper;
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}
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int get_lower() {
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return this->lower;
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}
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int get_count() {
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return this->count;
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}
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int get_answer() {
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return this->answer;
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}
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void reset() {
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this->upper = 999;
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this->lower = 0;
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this->count = 0;
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this->answer = rand() % 1000;
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}
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bool guess(int num) {
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this->count++;
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if (num == answer) return true;
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if (num > answer && num < this->upper) this->upper = num;
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else if (num < answer && num > this->lower) this->lower = num;
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return false;
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}
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};
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int main(int argc, char const *argv[]) {
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// initialize game
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srand(time(nullptr));
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Game game;
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// no port specified
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if (argc < 1) {
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cerr << "No port provided!" << endl << "Usage: server <port>" << endl;
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return NOPORT_RET;
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}
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int port = atoi(argv[1]);
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if (port < 0 || port >= 65536) {
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cerr << "Invalid port! port range: 0 ~ 65535" << endl;
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return INVALID_PORT_RET;
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}
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int sockfd = 0;
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struct sockaddr_in server_info;
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// create tcp socket
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sockfd = socket(AF_INET, SOCK_STREAM, 0);
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if (sockfd == -1) {
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cerr << "Failed to create socket" << endl;
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}
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// setup server info
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bzero((char *) &server_info, sizeof(server_info));
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server_info.sin_family = PF_INET;
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server_info.sin_addr.s_addr = INADDR_ANY;
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server_info.sin_port = htons(port);
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// bind
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if (bind(sockfd, (struct sockaddr *) &server_info, sizeof(server_info)) == -1) {
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cerr << "Cannot bind socker." << endl;
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close(sockfd);
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return BINDERR_RET;
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}
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// only one connection at the same time
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if (listen(sockfd, 1) == -1) {
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cerr << "Cannot listen to socket." << endl;
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return LISTENERR_RET;
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}
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cout << "Server up. Waiting connection..." << endl;
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int client_sockfd = 0;
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struct sockaddr_in client_info;
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socklen_t addrlen = sizeof(client_info);
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while (true) {
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client_sockfd = accept(sockfd, (struct sockaddr *) &client_info, &addrlen);
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if (client_sockfd < 0) {
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cout << "Error occurred while handling request from client." << endl;
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continue;
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}
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// retrieve client info
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char ip[INET_ADDRSTRLEN];
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uint16_t port;
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inet_ntop(AF_INET, &client_info.sin_addr, ip, sizeof(ip));
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port = ntohs(client_info.sin_port);
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cout << "New client from " << ip << ":" << port << " has connected!" << endl;
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// reset for new client
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game.reset();
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while (true) {
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// clear buffer for receive message
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char buffer[BUFFER_SIZE];
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memset(buffer, 0, sizeof(buffer));
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// wait message
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if (recv(client_sockfd, buffer, sizeof(buffer), 0) <= 0) {
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// closed connection
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cout << "Disconnected." << endl;
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break;
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}
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int guess = atoi(buffer);
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#ifdef DEBUG
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cout << guess << endl;
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#endif
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// message
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stringstream ss;
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const char * msg;
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#ifdef DEBUG
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cout << msg << endl;
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#endif
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// generate payload
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if (game.guess(guess)) {
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// win
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ss << game.get_answer() << ":" << game.get_answer() << ":" << game.get_count();
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// new turn for this client
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game.reset();
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} else {
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ss << game.get_lower() << ":" << game.get_upper() << ":" << game.get_count();
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}
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msg = ss.str().c_str();
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// send to client
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send(client_sockfd, msg, strlen(msg), 0);
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}
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}
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close(sockfd);
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return 0;
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} |