linux下使用c做简单的网络编程 ...

服务器端：

/* server.c*/
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <sys/types.h>
#include <arpa/inet.h>

#define MAXLINE 80
#define SERV_PORT 8000

int main(void)
{
 struct sockaddr_in servaddr, cliaddr;
 socklen_t cliaddr_len;
 int listenfd, connfd;
 char buf[MAXLINE];
 char str[INET_ADDRSTRLEN];
 int i, n;
 
 listenfd = socket(AF_INET, SOCK_STREAM, 0);
 
// bzero(&servaddr, sizeof(servaddr));
  memset(&servaddr, 0, sizeof(servaddr));
 servaddr.sin_family = AF_INET;
 servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
 servaddr.sin_port = htons(SERV_PORT);
 
 bind(listenfd, (struct sockaddr *)&servaddr, sizeof(servaddr));
 
 listen(listenfd, 20);
 printf("Accepting connections  ... \n");
 
 while(1){
  cliaddr_len = sizeof(cliaddr);
  connfd = accept(listenfd, (struct sockaddr *)&cliaddr, &cliaddr_len);
  
  n = read(connfd, buf, MAXLINE);
  
  printf("received from %s at PORT %d \n",
          inet_ntop(AF_INET, &cliaddr.sin_addr, str, sizeof(str)),
          ntohs(cliaddr.sin_port));
  for(i = 0; i<n; i++){
   buf[i] = toupper(buf[i]);   
  }
  write(connfd, buf, n);
  close (connfd);
 }
        return 1;
}

客户端：

/*client.c*/
#include <stdlib.h>
#include <stdio.h>
#include <string>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <sys/types.h>
#include <arpa/inet.h>

#define SERV_PORT 8000
#define MAXLINE 80

int main(int argc, char **argv)
{
 struct sockaddr_in servaddr;
 char buf[MAXLINE];
 int sockfd, n;
 char *name;

  if(argc==2){
    name = argv[1];
  }
  printf("you input name is %s;\n",name);
  fflush(stdout); 
  sockfd = socket(AF_INET, SOCK_STREAM, 0);
 
  memset(&servaddr, 0, sizeof(servaddr));
  servaddr.sin_family = AF_INET;
  inet_pton(AF_INET, "192.168.0.86", &servaddr.sin_addr);
  servaddr.sin_port = htons(SERV_PORT);
 
 connect(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr));
 
 write(sockfd, name, strlen(name));
 
 n = read(sockfd, buf, MAXLINE);
 printf("Response form server:\n");
 write(STDOUT_FILENO, buf, n);
 
 close(sockfd);
 
 return 0;
}