简单的tcp服务端/客户端代码例一

客户端：(client1.c)

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

#define BUFSIZE 1024
#define SERV_IP "127.0.0.1"
#define SERV_PORT 6666
int main()
{
        int cfd;
        int n;
        char buf[BUFSIZE];
        struct sockaddr_in serv_addr;
        //socklen_t serv_addr_len;
        cfd = socket(AF_INET, SOCK_STREAM, 0);

        memset(&serv_addr, 0, sizeof(serv_addr));
        serv_addr.sin_family = AF_INET;
        serv_addr.sin_port = htons(SERV_PORT);
        inet_pton(AF_INET, SERV_IP, &serv_addr.sin_addr.s_addr);
        if(connect(cfd, (struct sockaddr *)&serv_addr, sizeof(serv_addr))<0)
        {
                perror("connect");
                exit(1);
        }

        while(1)
        {
                fgets(buf, sizeof(buf), stdin);
                write(cfd, buf, strlen(buf));
                n = read(cfd, buf, sizeof(buf));
                write(STDOUT_FILENO, buf, n);
        }

        close(cfd);
        return 0;
}

服务端：(server1.c)

#include<stdio.h>
#include<unistd.h>
#include<sys/socket.h>
#include<stdlib.h>
#include<arpa/inet.h>
#include<ctype.h>
#include<string.h>
#define SERV_PORT 6666
#define BUFSIZE 1024
#define SERV_IP "127.0.0.1"

int main()
{
    int lfd,cfd;
    int n;
    char buf[BUFSIZE];
    struct sockaddr_in serv_addr,clie_addr;
    socklen_t clie_addr_len;
    lfd=socket(AF_INET,SOCK_STREAM,0);
    
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(SERV_PORT);
    serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    //memset(&serv_addr, 0, sizeof(serv_addr));
        //inet_pton(AF_INET, SERV_IP, &serv_addr.sin_addr.s_addr);


    if(bind(lfd,(struct sockaddr *) &serv_addr, sizeof(serv_addr))==-1)
    {
        perror("bind");
        exit(1);
    }

    if(listen(lfd,128)==-1)
    {
        perror("listen");
        exit(1);
    }

    clie_addr_len = sizeof(clie_addr);
    cfd = accept(lfd, (struct sockaddr *) & clie_addr, &clie_addr_len);
    if(cfd<0)
    {
        perror("accept");
        exit(1);
    }
    while(1)
    {
        n = read (cfd, buf, sizeof(buf));
        for (int i = 0; i < n; i++)
            buf[i] = toupper(buf[i]);
        write (cfd, buf, n);

    }
    close(cfd);
    close(lfd);
    return 0;
}