C语言实现TCP CS模型代码，客户端服务器

#include <stdio.h> 
#include <stdlib.h> 
#include <string.h> 
#include <sys/socket.h> 
#include <netinet/in.h> 
#include <arpa/inet.h> 
#include <unistd.h> 
#include <ctype.h> 
 
 
#define PORT        8080 
#define BUFFER_SIZE 1024 
 
 
int main() { 
    int socket_fd, conn_fd; 
    socklen_t cli_len; 
    struct sockaddr_in serv_addr, cli_addr; 
    char buffer[BUFFER_SIZE]; 
 
 
    // 创建socket 
    if ((socket_fd = socket(AF_INET, SOCK_STREAM, 0)) == -1) { 
        perror("Socket creation failed"); 
        exit(EXIT_FAILURE); 
    } 
 
 
    // 初始化地址和端口 
    memset(&serv_addr, 0, sizeof(serv_addr)); 
    serv_addr.sin_family = AF_INET; 
    serv_addr.sin_addr.s_addr = INADDR_ANY; 
    serv_addr.sin_port = htons(PORT); 
 
 
    // 绑定地址和端口 
    if (bind(socket_fd, (const struct sockaddr*)&serv_addr, sizeof(serv_addr)) == -1) { 
        perror("Bind failed"); 
        exit(EXIT_FAILURE); 
    } 
 
 
    // 监听连接 
    if (listen(socket_fd, 10) == -1) { 
        perror("Listen failed"); 
        exit(EXIT_FAILURE); 
    } 
 
 
    printf("Server started at port %d ...\n", PORT); 
 
 
    while(1) { 
        // 接受连接请求 
        cli_len = sizeof(cli_addr); 
        conn_fd = accept(socket_fd, (struct sockaddr*)&cli_addr, &cli_len); 
        if (conn_fd == -1) { 
            perror("Accept failed"); 
            exit(EXIT_FAILURE); 
        } 
 
 
        printf("Accepted client connection from %s:%d\n", inet_ntoa(cli_addr.sin_addr), ntohs(cli_addr.sin_port)); 
 
 
        while(1) { 
            // 接受客户端发送的数据 
            memset(buffer, 0, sizeof(buffer)); 
            if (recv(conn_fd, buffer, sizeof(buffer), 0) == -1) { 
                perror("Receive failed"); 
                exit(EXIT_FAILURE); 
            } 
 
 
            // 转换为大写形式 
            for (int i = 0; i < strlen(buffer); i++) { 
                buffer[i] = toupper(buffer[i]); 
            } 
 
 
            // 发送数据回客户端 
            if (send(conn_fd, buffer, strlen(buffer), 0) == -1) { 
                perror("Send failed"); 
                exit(EXIT_FAILURE); 
            } 
 
 
            // 输出客户端发来的数据 
            printf("Received data from %s:%d: %s\n", inet_ntoa(cli_addr.sin_addr), ntohs(cli_addr.sin_port), buffer); 
        } 
 
 
        // 关闭连接 
        close(conn_fd); 
    } 
 
 
    // 关闭监听 
    close(socket_fd); 
 
 
    return 0; 
} 

#include <stdio.h> 
#include <stdlib.h> 
#include <string.h> 
#include <sys/socket.h> 
#include <netinet/in.h> 
#include <arpa/inet.h> 
#include <unistd.h> 
 
 
#define PORT        8080 
#define BUFFER_SIZE 1024 
 
 
int main() { 
    int socket_fd; 
    struct sockaddr_in serv_addr; 
    char buffer[BUFFER_SIZE]; 
 
 
    // 创建socket 
    if ((socket_fd = socket(AF_INET, SOCK_STREAM, 0)) == -1) { 
        perror("Socket creation failed"); 
        exit(EXIT_FAILURE); 
    } 
 
 
    // 初始化地址和端口 
    memset(&serv_addr, 0, sizeof(serv_addr)); 
    serv_addr.sin_family = AF_INET; 
    serv_addr.sin_addr.s_addr = INADDR_ANY; 
    serv_addr.sin_port = htons(PORT); 
 
 
    // 连接到服务器 
    if (connect(socket_fd, (const struct sockaddr*)&serv_addr, sizeof(serv_addr)) == -1) { 
        perror("Connect failed"); 
        exit(EXIT_FAILURE); 
    } 
 
 
    printf("Connected to server at %s:%d ...\n", inet_ntoa(serv_addr.sin_addr), ntohs(serv_addr.sin_port)); 
 
 
    while(1) { 
        // 从标准输入读取要发送的数据 
        memset(buffer, 0, sizeof(buffer)); 
        printf("Please enter data to send to server (type \"exit\" to quit):\n"); 
        fgets(buffer, sizeof(buffer), stdin); 
 
 
        // 退出循环 
        if (strcmp(buffer, "exit\n") == 0) { 
            close(socket_fd); 
            exit(EXIT_SUCCESS); 
        } 
 
 
        // 发送数据到服务器 
        if (send(socket_fd, buffer, strlen(buffer), 0) == -1) { 
            perror("Send failed"); 
            exit(EXIT_FAILURE); 
        } 
 
 
        // 接受服务器返回的数据 
        memset(buffer, 0, sizeof(buffer)); 
        if (recv(socket_fd, buffer, sizeof(buffer), 0) == -1) { 
            perror("Receive failed"); 
            exit(EXIT_FAILURE); 
        } 
 
 
        // 输出服务器返回的数据 
        printf("Received data from server: %s\n", buffer); 
    } 
 
 
    return 0; 
}