客户端、服务器代码实例

服务器：

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <netdb.h>
#include <errno.h>

#define PORT 2345
#define MAXSIZE 1024

int main(void)
{
    int sockfd, newsockfd;
    int sin_size, portnumber;
    char buf[MAXSIZE] = {0};
    struct sockaddr_in server_addr;
    struct sockaddr_in client_addr;
    int client_addr_len = sizeof(struct sockaddr_in);

    //creat socket
    if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
    {
        fprintf(stderr, "creat socket failed
");
        exit(EXIT_FAILURE);
    }    
    printf("create socket success!
");
    printf("sockfd is %d
", sockfd);  
    
    bzero(&server_addr, sizeof(struct sockaddr_in));
    server_addr.sin_family = AF_INET;    //TCP/IP
    server_addr.sin_port = htons(PORT); //socket port
    server_addr.sin_addr.s_addr = htonl(INADDR_ANY);  //inet_addr("0.0.0.0")
    
    //bind sockfd and ip addr and port
    if (bind(sockfd, (struct sockaddr*)(&server_addr), sizeof(struct sockaddr)) < 0)
    {
        fprintf(stderr, "bind failed 
");
        exit(EXIT_FAILURE);
    }
    printf("bind success!
");
     
     //listen sockfd, passive wait
    if (listen(sockfd, 10) < 0)
    {
        perror("listen fail
");
    }
    puts("start listen!
");
    
    //accept
    if((newsockfd = accept(sockfd, (struct sockaddr *)(&client_addr), &client_addr_len)) < 0)
    {
        perror("accept error");
        exit(EXIT_FAILURE);
    }    
    printf("accepted a new connection!
");
    printf("The new socket id is %d
", newsockfd);
    printf("Accept client ip is %s
", inet_ntoa(client_addr.sin_addr));
    printf("Connet successful, please client input message
");
    
    //send message
    char sendbuf[MAXSIZE] = {0};
    while (1)
    {
        int len = recv(newsockfd, buf, sizeof(buf), 0);
        if (strcmp(buf, "exit
") == 0)
            break;
        fputs(buf, stdout);
        send(newsockfd, buf, len, 0);
        memset(sendbuf, 0, sizeof(sendbuf));
        memset(buf, 0 , sizeof(buf));
    }    

    close(newsockfd);
    close(sockfd);
    printf("exit success
");
    exit(EXIT_SUCCESS);
    return 0;
}

客户端：

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <netdb.h>
#include <errno.h>

#define PORT 2345
#define MAXSIZE 1024


int main(void)
{
    int sockfd;
    char buffer[1024] = {0};
    struct sockaddr_in server_addr;
    struct hostent *host;
    int nbytes;
    if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
    {
        fprintf(stderr, "Socket Error is %s
", strerror(errno));
        exit(EXIT_FAILURE);
    }
    bzero(&server_addr, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(PORT);
    server_addr.sin_addr.s_addr = htonl(INADDR_ANY);

    if(connect(sockfd, (struct sockaddr *)(&server_addr), sizeof(struct sockaddr)) < 0)
    {
        fprintf(stderr, "Connect failed
");
        exit(EXIT_FAILURE);
    }
    char sendbuf[MAXSIZE] = {0};
    char recvbuf[MAXSIZE] = {0};
    while (1)
    {
        fgets(sendbuf, sizeof(sendbuf), stdin);
        send(sockfd, sendbuf, strlen(sendbuf), 0);
        if (strcmp(sendbuf, "exit
") == 0)
            break;    
        recv(sockfd, recvbuf, sizeof(recvbuf), 0);
        fputs(recvbuf, stdout);
        memset(sendbuf, 0, sizeof(sendbuf));
        memset(recvbuf, 0, sizeof(recvbuf));
    }
    close(sockfd);
    exit(EXIT_SUCCESS);
    return 0;
}