Linux下的C语言编程——简单实现tcp客户端和服务器

来源：互联网发布：中老年品位知乎编辑：程序博客网时间：2024/06/05 09:41

以下程序均未做错误处理，等有时间一定完善

客户端

#include <stdio.h>#include <sys/socket.h>#include <stdlib.h>#include <netinet/in.h>#include <string.h>int main(int argc,char **argv){int sockfd;int n;struct sockaddr_in servaddr,cliaddr;char sendbuf[1000];char recvbuf[1000];if(argc != 2){printf("usage:client <ip address>\n");exit(-1);}sockfd = socket(AF_INET,SOCK_STREAM,0);bzero(&servaddr,sizeof(servaddr));servaddr.sin_family = AF_INET;servaddr.sin_addr.s_addr = inet_addr(argv[1]);servaddr.sin_port = htons(3200);connect(sockfd,(struct sockaddr*)&servaddr,sizeof(servaddr));while(fgets(sendbuf,1000,stdin) != NULL){sendto(sockfd,sendbuf,strlen(sendbuf),0,(struct sockaddr *)&servaddr,sizeof(servaddr));n = recvfrom(sockfd,recvbuf,1000,0,NULL,NULL);//(struct sockaddr*)&cliaddr,recvbuf[n] = '\0';fputs(recvbuf,stdout);}close(sockfd);    return 0;}

服务器

#include <stdio.h>#include <string.h>#include <stdlib.h>#include <netinet/in.h>#include <sys/socket.h>void strlwr(char *str){char *p;p = str;while(*p != '\0'){if((*p >= 'a') && (*p <= 'z')){*p -= 32;}p++;}}int main(){pid_t pid;int listenfd,connfd;int n;struct sockaddr_in servaddr,cliaddr;socklen_t clilen;char mesg[1000];listenfd = socket(AF_INET,SOCK_STREAM,0);bzero(&servaddr,sizeof(servaddr));servaddr.sin_family = AF_INET;servaddr.sin_addr.s_addr = htonl(INADDR_ANY);servaddr.sin_port = htons(3200);int opt = 1;setsockopt(listenfd,SOL_SOCKET,SO_REUSEADDR,&opt,sizeof(opt));bind(listenfd,(struct sockaddr *)&servaddr,sizeof(servaddr));listen(listenfd,1024);for(;;){clilen = sizeof(cliaddr);connfd = accept(listenfd,(struct sockaddr*)&cliaddr,&clilen);if((pid = fork()) == 0){close(listenfd);for(;;){n = recvfrom(connfd,mesg,1000,0,(struct sockaddr*)&cliaddr,&clilen);if(n == 0){printf("client closed!\n");exit(-1);}printf("********************\n");mesg[n] = '\0';printf("%s\n",mesg);printf("*********************\n");strlwr(mesg);sendto(connfd,mesg,n,0,(struct sockaddr *)&cliaddr,sizeof(cliaddr));}close(connfd);}}close(listenfd);    return 0;}

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