服务器端

#include <unistd.h>
#include <sys/socket.h>
#include <stdio.h>
#include <strings.h>
#include <iostream>
#include <netinet/in.h>
#include <stdlib.h>
#include <arpa/inet.h>
using namespace std;
int
main(int argc,char ** argv)
{
        struct sockaddr_in servaddr,cliaddr;
        bzero(&servaddr,sizeof(servaddr));
        if(argc==2)
                servaddr.sin_port=atoi(argv[1]);
        else if(argc==3){
                servaddr.sin_port=atoi(argv[2]);
                inet_pton(AF_INET,argv[1],&servaddr.sin_addr);
        }
        else{
                cout<<"USAGE: [<host>] <port>"<<endl;
                exit(0);
        }
        servaddr.sin_family=AF_INET;
        int fd;
        fd=socket(AF_INET,SOCK_STREAM,0);
        bind(fd,(struct sockaddr*)&servaddr,sizeof(servaddr));
        listen(fd,5);
        int connfd;socklen_t clilen;
        for(;;){
                connfd=accept(fd,(struct sockaddr*)&cliaddr,&clilen);
                cout<<"guess is coming"<<endl;
                char rbuf[2000],wbuf[2000];
                int n=-1;
                for(;;){
                        n=read(connfd,rbuf,2000);
                        if(n==0)
                                break;
                        write(connfd,rbuf,n);
                }
        }
}

客户端

#include "unp.h"
#include <iostream>
using namespace std;
int
main(int argc, char **argv)
{
        int fd,n;
        fd=socket(AF_INET,SOCK_STREAM,0);
        struct sockaddr_in servaddr;
        servaddr.sin_family=AF_INET;
        if(argc!=3){
                cout<<"USAGE:<host> <port>"<<endl;
                exit(0);
        }
        else{
                servaddr.sin_port=atoi(argv[2]);
                inet_pton(AF_INET,argv[1],&servaddr.sin_addr);
        }
        connect(fd,(struct sockaddr*)&servaddr,sizeof(servaddr));
        char wbuf[2000],rbuf[2000];

        while(fgets(wbuf,2000,stdin)!=NULL){
                write(fd,wbuf,strlen(wbuf));
                n=read(fd,rbuf,2000);
                fputs(rbuf,stdout);
        }
}

结果

image.png

image.png