哈工大计算机网络实验一：TCP/IP编程

要求：编写一个简单的 Client/Server 网络应用程序。

要求实现客户向服务器传输任意一个字符串,服务器将收到的字符串变换成大写后传回客户。

服务器端程序:

server_tcp.c

#include 
#include 
#include 
#include 
#include 
#include 

int main()
{
	// set buffer array
	char buffer[100] = {0};
	// set flag
	int flag;
	// set loop i
	int i;


	int sfp,nfp;
	struct sockaddr_in s_add,c_add;
	int sin_size;
	unsigned short portnum=0x8888;
	printf("Hello,welcome to my server !\r\n");
	sfp = socket(AF_INET, SOCK_STREAM, 0);
	if(-1 == sfp)
	{
		printf("socket fail ! \r\n");
		return -1;
	}
	printf("socket ok !\r\n");

	bzero(&s_add,sizeof(struct sockaddr_in));
	s_add.sin_family=AF_INET;
	s_add.sin_addr.s_addr=htonl(INADDR_ANY);
	s_add.sin_port=htons(portnum);

	if(-1 == bind(sfp,(struct sockaddr *)(&s_add), sizeof(struct sockaddr)))
	{
		printf("bind fail !\r\n");
		return -1;
	}
	printf("bind ok !\r\n");

	if(-1 == listen(sfp,5))
	{
		printf("listen fail !\r\n");
		return -1;
	}
	printf("listen ok\r\n");

	nfp = accept(sfp, (struct sockaddr *)(&c_add), &sin_size);
	if(-1 == nfp)
	{
		printf("accept fail !\r\n");
		return -1;
	}
	printf("accept ok!\r\nServer start get connect from %#x : %#x\r\n",ntohl(c_add.sin_addr.s_addr),ntohs(c_add.sin_port));
	
	while(1)
	{
		sin_size = sizeof(struct sockaddr_in);


		//read data from client
		if(-1 == (flag = read(nfp , buffer,1024)))	
		{
			printf ("read from client fail!\r\n");
		}
		//printf ("%s\r\n",buffer);
		// lower to upper	
		for (i = 0 ;i < 100;i++)
		{
			if(buffer[i]>='a' && buffer[i]<='z')
			   // printf("%c",buffer[i]);
			   buffer[i] = buffer [i] - 32;
		
		}
		//printf ("\n");
		//printf ("%s\r\n",buffer);
		//printf ("size:%d\n",(buffer));
		if(-1 == write(nfp,buffer,32))
		{
			printf("write to client fail!\r\n");
			return -1;
		}
		printf("write to client ok!\r\n");
		//memset(buffer,0,100);
	}
	close(nfp);
	close(sfp);
	return 0;
}

客户端程序 ：client_tcp.c

#include 
#include 
#include 
#include 
#include 
#include 
int main()
{
	// set str array
	char str[100]={0};
	char c;

	int cfd;
	int recbytes;
	int sin_size;
	char buffer[1024]={0};   
	struct sockaddr_in s_add,c_add;
	unsigned short portnum=0x8888; 
	printf("Hello,welcome to client !\r\n");

	cfd = socket(AF_INET, SOCK_STREAM, 0);
	if(-1 == cfd)
	{
		printf("socket fail ! \r\n");
		return -1;
	}
	printf("socket ok !\r\n");

	bzero(&s_add,sizeof(struct sockaddr_in));
	s_add.sin_family=AF_INET;
	s_add.sin_addr.s_addr= inet_addr("0.0.0.0");
	s_add.sin_port=htons(portnum);
	printf("s_addr = %#x ,port : %#x\r\n",s_add.sin_addr.s_addr,s_add.sin_port);

	if(-1 == connect(cfd,(struct sockaddr *)(&s_add), sizeof(struct sockaddr)))
	{
		printf("connect fail !\r\n");
		return -1;
	}
	printf("connect ok !\r\n");

	//write data to server
	while(1){
		int j = 0;
		printf("wait for input :");
		memset(str,0,100);
		while((c=getchar())!='\n')	
		{
			str[j] = c;
			j++;

		}
		write (cfd,str,32);
		//printf("%s\n",str);
		if(-1 == (recbytes = read(cfd,buffer,1024)))
		{
			printf("read from server fail !\r\n");
			return -1;
		}
		printf("data from server is :");
		printf("%s\n",buffer);
		//buffer[recbytes]='\0';
		//printf("%s\r\n",buffer);
		//getchar();
	}
	close(cfd);
	return 0;
}