用c语言写一个客户端和服务器的双向通信的程序

以下是一个使用 C 语言编写的简单的客户端和服务器的双向通信程序：

服务器端代码：

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

#define PORT 9999

int main() {
    int server_fd, new_socket, valread;
    struct sockaddr_in address;
    int opt = 1;
    int addrlen = sizeof(address);
    char buffer[1024] = {0};
    char *hello = "Hello from server";
    
    // 创建 socket
    if ((server_fd = socket(AF_INET, SOCK_STREAM, 0)) == 0) {
        perror("socket failed");
        exit(EXIT_FAILURE);
    }
    
    // 设置 socket 选项，允许地址重用
    if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR | SO_REUSEPORT, &opt, sizeof(opt))) {
        perror("setsockopt");
        exit(EXIT_FAILURE);
    }
    
    address.sin_family = AF_INET;
    address.sin_addr.s_addr = INADDR_ANY;
    address.sin_port = htons(PORT);
    
    // 绑定 socket
    if (bind(server_fd, (struct sockaddr *)&address, sizeof(address)) < 0) {
        perror("bind failed");
        exit(EXIT_FAILURE);
    }
    
    // 监听 socket
    if (listen(server_fd, 3) < 0) {
        perror("listen");
        exit(EXIT_FAILURE);
    }
    
    // 接受连接
    if ((new_socket = accept(server_fd, (struct sockaddr *)&address, (socklen_t*)&addrlen)) < 0) {
        perror("accept");
        exit(EXIT_FAILURE);
    }
    
    // 接收并发送数据
    while(1) {
        valread = read(new_socket, buffer, 1024);
        printf("Client: %s\n", buffer);
        memset(buffer, 0, sizeof(buffer));
        printf("Server: ");
        scanf("%s", buffer);
        send(new_socket, buffer, strlen(buffer), 0);
    }
    
    return 0;
}

客户端代码：

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

#define PORT 9999

int main() {
    int sock = 0, valread;
    struct sockaddr_in serv_addr;
    char buffer[1024] = {0};
    char *hello = "Hello from client";
    
    // 创建 socket
    if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
        printf("\n Socket creation error \n");
        return -1;
    }
    
    memset(&serv_addr, '0', sizeof(serv_addr));
    
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(PORT);
    
    // 将 IP 地址从点十进制转换为二进制格式
    if (inet_pton(AF_INET, "127.0.0.1", &serv_addr.sin_addr) <= 0) {
        printf("\nInvalid address/ Address not supported \n");
        return -1;
    }
    
    // 连接服务器
    if (connect(sock, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0) {
        printf("\nConnection Failed \n");
        return -1;
    }
    
    // 接收并发送数据
    while(1) {
        printf("Client: ");
        scanf("%s", buffer);
        send(sock, buffer, strlen(buffer), 0);
        memset(buffer, 0, sizeof(buffer));
        valread = read(sock, buffer, 1024);
        printf("Server: %s\n", buffer);
        memset(buffer, 0, sizeof(buffer));
    }
    
    return 0;
}

这个程序中，服务器端和客户端通过 socket 建立连接，然后进行双向通信。服务器端监听端口 9999，并在接收到客户端连接请求后，不断接收客户端发送的消息并回复消息。客户端连接到服务器后，从命令行接收用户输入的消息，并将其发送给服务器，然后接收服务器的回复，并将其输出到命令行。