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 <stdlib.h>#include <sys/types.h>#include <stdio.h>#include <sys/socket.h>#include <netinet/in.h>#include <string.h>int main(){// set buffer arraychar buffer[100] = {0};// set flagint flag;// set loop iint 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 clientif(-1 == (flag = read(nfp , buffer,1024))){printf ("read from client fail!\r\n");}//printf ("%s\r\n",buffer);// lower to upperfor (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 <stdlib.h>#include <sys/types.h>#include <stdio.h>#include <sys/socket.h>#include <netinet/in.h>#include <string.h>int main(){// set str arraychar 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 serverwhile(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;}