linux网络编程客户端实现client.c

client.c

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

#define SERV_IP "127.0.0.1"
#define SERV_PORT 6666

int main(void)
{
	int cfd;
	struct sockaddr_in serv_addr;
	char buf[BUFSIZ];
	int n;

	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);//把本地字节序转化为网络字节序
	inet_pton(AF_INET,SERV_IP,&serv_addr.sin_addr.s_addr);

	connect(cfd,(struct sockaddr *)&serv_addr,sizeof(serv_addr));

	while(1){
		fgets(buf,sizeof(buf),stdin);//hello world --- fgets --->"hello world\n\0"
		write(cfd,buf,strlen(buf));
		n=read(cfd,buf,sizeof(buf));
		write(STDOUT_FILENO,buf,n);
	}
	close(cfd);

	return 0;
}

server.c

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

#define SERV_IP "127.0.0.1"
#define SERV_PORT 6666

int main(void)
{
	int lfd,cfd;
	struct sockaddr_in serv_addr,clie_addr;
	socklen_t clie_addr_len;
	char buf[BUFSIZ],clie_IP[BUFSIZ];
	int n,i;

	lfd=socket(AF_INET,SOCK_STREAM,0);

	serv_addr.sin_family=AF_INET;
	serv_addr.sin_port=htons(SERV_PORT);//把本地字节序转化为网络字节序
	serv_addr.sin_addr.s_addr=htonl(INADDR_ANY);//翻译为本地任意字节序

	bind(lfd,(struct sockaddr *)&serv_addr,sizeof(serv_addr));

	listen(lfd,128);

	clie_addr_len=sizeof(clie_addr);
	cfd=accept(lfd,(struct sockaddr *)&clie_addr,&clie_addr_len);

	printf("client IP:%s,client port:%d\n",
			inet_ntop(AF_INET,&clie_addr.sin_addr.s_addr,clie_IP,sizeof(clie_IP)),
			ntohs(clie_addr.sin_port));
	while(1){
		n=read(cfd,buf,sizeof(buf));
		for(i=0;i<n;i++)
			buf[i]=toupper(buf[i]);
		write(cfd,buf,n);
	}
	close(lfd);
	close(cfd);
	return 0;
}

启动两个终端，在server终端上输入：

gcc -pthread server.c
./server

在client终端上输入：

gcc -pthread client.c
./client