帮我用c++写windows下基于socket通信的聊天室服务器与客户端实现的代码 完成功能： 1.用户注册功能； 2.两个用户服务器发送私密消息； 3.用户创建一个或多个聊天群组； 4.用户加入群组、在群组内发送消息、离开群组； 5.用户之间的聊天信息通过服务器端转发；

以下是基于socket通信的聊天室服务器与客户端的代码，实现了您所要求的功能：

服务器端代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <winsock2.h>

#pragma comment(lib,"ws2_32.lib") //Winsock Library

#define MAX_CLIENTS 30
#define MAX_GROUPS 5
#define MAX_GROUP_SIZE 10
#define MAX_USERNAME_LENGTH 20
#define MAX_MESSAGE_LENGTH 100

typedef struct {
    char username[MAX_USERNAME_LENGTH];
    SOCKET socket;
    int in_group;
    int group_id;
} client;

typedef struct {
    char name[MAX_USERNAME_LENGTH];
    int clients[MAX_GROUP_SIZE];
    int num_clients;
} group;

client clients[MAX_CLIENTS];
group groups[MAX_GROUPS];
int num_clients = 0;
int num_groups = 0;

void send_message_to_all(char* message, int sender_id) {
    int i;
    for (i = 0; i < num_clients; i++) {
        if (i != sender_id) {
            send(clients[i].socket, message, strlen(message), 0);
        }
    }
}

void send_message_to_group(char* message, int sender_id, int group_id) {
    int i;
    for (i = 0; i < groups[group_id].num_clients; i++) {
        int client_id = groups[group_id].clients[i];
        if (client_id != sender_id) {
            send(clients[client_id].socket, message, strlen(message), 0);
        }
    }
}

void add_client_to_group(int client_id, int group_id) {
    clients[client_id].in_group = 1;
    clients[client_id].group_id = group_id;

    groups[group_id].clients[groups[group_id].num_clients] = client_id;
    groups[group_id].num_clients++;
}

void remove_client_from_group(int client_id) {
    int group_id = clients[client_id].group_id;

    int i;
    for (i = 0; i < groups[group_id].num_clients; i++) {
        if (groups[group_id].clients[i] == client_id) {
            groups[group_id].num_clients--;
            groups[group_id].clients[i] = groups[group_id].clients[groups[group_id].num_clients];
            break;
        }
    }

    clients[client_id].in_group = 0;
    clients[client_id].group_id = -1;
}

void handle_client_message(int client_id, char* message) {
    if (strncmp(message, "/register ", 10) == 0) {
        char* username = message + 10;
        strncpy(clients[client_id].username, username, MAX_USERNAME_LENGTH);
        printf("Client %d registered as %s\n", client_id, clients[client_id].username);
        send(clients[client_id].socket, "Registered successfully.\n", 25, 0);
    } else if (strncmp(message, "/private ", 9) == 0) {
        char* recipient_username = message + 9;
        char* message_text = strchr(recipient_username, ' ');
        if (message_text == NULL) {
            send(clients[client_id].socket, "Invalid command.\n", 17, 0);
            return;
        }
        *message_text = '\0';
        message_text++;

        int i;
        int recipient_id = -1;
        for (i = 0; i < num_clients; i++) {
            if (strcmp(clients[i].username, recipient_username) == 0) {
                recipient_id = i;
                break;
            }
        }
        if (recipient_id == -1) {
            send(clients[client_id].socket, "Recipient not found.\n", 22, 0);
            return;
        }

        char full_message[MAX_MESSAGE_LENGTH + MAX_USERNAME_LENGTH + 4];
        sprintf(full_message, "(private from %s): %s\n", clients[client_id].username, message_text);
        send(clients[recipient_id].socket, full_message, strlen(full_message), 0);
        send(clients[client_id].socket, "Message sent.\n", 15, 0);
    } else if (strncmp(message, "/create_group ", 14) == 0) {
        char* group_name = message + 14;

        if (num_groups >= MAX_GROUPS) {
            send(clients[client_id].socket, "Maximum number of groups reached.\n", 34, 0);
            return;
        }

        strncpy(groups[num_groups].name, group_name, MAX_USERNAME_LENGTH);
        groups[num_groups].num_clients = 0;
        send(clients[client_id].socket, "Group created.\n", 16, 0);

        add_client_to_group(client_id, num_groups);
        num_groups++;
    } else if (strncmp(message, "/join_group ", 12) == 0) {
        char* group_name = message + 12;

        int i;
        int group_id = -1;
        for (i = 0; i < num_groups; i++) {
            if (strcmp(groups[i].name, group_name) == 0) {
                group_id = i;
                break;
            }
        }
        if (group_id == -1) {
            send(clients[client_id].socket, "Group not found.\n", 18, 0);
            return;
        }

        if (groups[group_id].num_clients >= MAX_GROUP_SIZE) {
            send(clients[client_id].socket, "Group is full.\n", 16, 0);
            return;
        }

        add_client_to_group(client_id, group_id);
        send(clients[client_id].socket, "Group joined.\n", 15, 0);
    } else if (strncmp(message, "/leave_group", 12) == 0) {
        if (!clients[client_id].in_group) {
            send(clients[client_id].socket, "You are not in a group.\n", 24, 0);
            return;
        }

        remove_client_from_group(client_id);
        send(clients[client_id].socket, "Group left.\n", 13, 0);
    } else {
        if (clients[client_id].in_group) {
            char full_message[MAX_MESSAGE_LENGTH + MAX_USERNAME_LENGTH + 4];
            sprintf(full_message, "(%s): %s\n", clients[client_id].username, message);
            send_message_to_group(full_message, client_id, clients[client_id].group_id);
        } else {
            char full_message[MAX_MESSAGE_LENGTH + MAX_USERNAME_LENGTH + 4];
            sprintf(full_message, "(%s): %s\n", clients[client_id].username, message);
            send_message_to_all(full_message, client_id);
        }
    }
}

int main(int argc, char* argv[]) {
    WSADATA wsa;
    SOCKET master_socket, new_socket;
    struct sockaddr_in server, address;
    int addrlen = sizeof(address);
    char message[MAX_MESSAGE_LENGTH];
    int opt = 1;
    int i;

    //Initialise winsock
    printf("\nInitialising Winsock...");
    if (WSAStartup(MAKEWORD(2, 2), &wsa) != 0) {
        printf("Failed. Error Code : %d", WSAGetLastError());
        return 1;
    }
    printf("Initialised.\n");

    //Create a master socket
    if ((master_socket = socket(AF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET) {
        printf("Could not create socket : %d", WSAGetLastError());
    }

    //Set master socket to allow multiple connections
    if (setsockopt(master_socket, SOL_SOCKET, SO_REUSEADDR, (char*)&opt, sizeof(opt)) < 0) {
        printf("setsockopt");
    }

    //Bind the socket to localhost port 8888
    server.sin_family = AF_INET;
    server.sin_addr.s_addr = INADDR_ANY;
    server.sin_port = htons(8888);

    if (bind(master_socket, (struct sockaddr*)&server, sizeof(server)) == SOCKET_ERROR) {
        printf("Bind failed with error code : %d", WSAGetLastError());
    }

    //Listen for incoming connections
    listen(master_socket, 3);

    //Accept incoming connections
    puts("Waiting for connections...");
    while (1) {
        new_socket = accept(master_socket, (struct sockaddr*)&address, &addrlen);
        if (new_socket == INVALID_SOCKET) {
            printf("accept failed with error code : %d", WSAGetLastError());
            continue;
        }

        printf("New connection from %s:%d\n", inet_ntoa(address.sin_addr), ntohs(address.sin_port));

        //Add new client to array
        clients[num_clients].socket = new_socket;
        clients[num_clients].in_group = 0;
        clients[num_clients].group_id = -1;
        num_clients++;

        //Send welcome message to client
        send(new_socket, "Welcome to the chat server.\n", 28, 0);

        //Receive message from client
        while (1) {
            int num_bytes = recv(new_socket, message, MAX_MESSAGE_LENGTH, 0);
            if (num_bytes == SOCKET_ERROR) {
                printf("recv failed with error code : %d", WSAGetLastError());
                break;
            }

            if (num_bytes == 0) {
                printf("Connection closed by client.\n");
                break;
            }

            message[num_bytes] = '\0';
            printf("Received message from client %d: %s\n", num_clients - 1, message);

            handle_client_message(num_clients - 1, message);
        }

        //Remove client from array
        int client_id = num_clients - 1;
        closesocket(clients[client_id].socket);
        if (clients[client_id].in_group) {
            remove_client_from_group(client_id);
        }
        num_clients--;
    }

    closesocket(master_socket);
    WSACleanup();

    return 0;
}

客户端代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <winsock2.h>

#pragma comment(lib,"ws2_32.lib") //Winsock Library

#define MAX_MESSAGE_LENGTH 100

int main(int argc, char* argv[]) {
    WSADATA wsa;
    SOCKET s;
    struct sockaddr_in server;
    char message[MAX_MESSAGE_LENGTH];
    char server_reply[MAX_MESSAGE_LENGTH];
    int i;

    //Initialise winsock
    printf("\nInitialising Winsock...");
    if (WSAStartup(MAKEWORD(2, 2), &wsa) != 0) {
        printf("Failed. Error Code : %d", WSAGetLastError());
        return 1;
    }
    printf("Initialised.\n");

    //Create a socket
    if ((s = socket(AF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET) {
        printf("Could not create socket : %d", WSAGetLastError());
    }

    //Connect to remote server
    server.sin_addr.s_addr = inet_addr("127.0.0.1"); //localhost
    server.sin_family = AF_INET;
    server.sin_port = htons(8888);

    if (connect(s, (struct sockaddr*)&server, sizeof(server)) < 0) {
        perror("connect failed. Error");
        return 1;
    }

    //Receive welcome message from server
    if (recv(s, server_reply, MAX_MESSAGE_LENGTH, 0) < 0) {
        printf("recv failed with error code : %d", WSAGetLastError());
    }
    printf("%s", server_reply);

    //Register with server
    printf("Enter username: ");
    fgets(message, MAX_MESSAGE_LENGTH, stdin);
    message[strlen(message) - 1] = '\0'; //remove newline character
    sprintf(server_reply, "/register %s", message);
    if (send(s, server_reply, strlen(server_reply), 0) < 0) {
        printf("send failed with error code : %d", WSAGetLastError());
    }
    if (recv(s, server_reply, MAX_MESSAGE_LENGTH, 0) < 0) {
        printf("recv failed with error code : %d", WSAGetLastError());
    }
    printf("%s", server_reply);

    //Enter main loop
    while (1) {
        printf("Enter message: ");
        fgets(message, MAX_MESSAGE_LENGTH, stdin);
        message[strlen(message) - 1] = '\0'; //remove newline character

        if (strncmp(message, "/private ", 9) == 0) {
            if (send(s, message, strlen(message), 0) < 0) {
                printf("send failed with error code : %d", WSAGetLastError());
            }
            if (recv(s, server_reply, MAX_MESSAGE_LENGTH, 0) < 0) {
                printf("recv failed with error code : %d", WSAGetLastError());
            }
            printf("%s", server_reply);
        } else if (strncmp(message, "/create_group ", 14) == 0) {
            if (send(s, message, strlen(message), 0) < 0) {
                printf("send failed with error code : %d", WSAGetLastError());
            }
            if (recv(s, server_reply, MAX_MESSAGE_LENGTH, 0) < 0) {
                printf("recv failed with error code : %d", WSAGetLastError());
            }
            printf("%s", server_reply);
        } else if (strncmp(message, "/join_group ", 12) == 0) {
            if (send(s, message, strlen(message), 0) < 0) {
                printf("send failed with error code : %d", WSAGetLastError());
            }
            if (recv(s, server_reply, MAX_MESSAGE_LENGTH, 0) < 0) {
                printf("recv failed with error code : %d", WSAGetLastError());
            }
            printf("%s", server_reply);
        } else if (strncmp(message, "/leave_group", 12) == 0) {
            if (send(s, message, strlen(message), 0) < 0) {
                printf("send failed with error code : %d", WSAGetLastError());
            }
            if (recv(s, server_reply, MAX_MESSAGE_LENGTH, 0) < 0) {
                printf("recv failed with error code : %d", WSAGetLastError());
            }
            printf("%s", server_reply);
        } else {
            if (send(s, message, strlen(message), 0) < 0) {
                printf("send failed with error code : %d", WSAGetLastError());
            }
        }
    }

    closesocket(s);
    WSACleanup();

    return 0;
}