网络编程

客户端代码如下

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<unistd.h>
#include<sys/stat.h>
#include<arpa/inet.h>
#include<sys/socket.h>
int main(){
    int ssock,len;
    char buf[100];
    char client[100]="this is from client";//用来发送给server
    struct sockaddr_in server_addr;//结构体sockaddr_in包含里各种参数
    if((ssock=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP))<0){
        perror("socket error");//如果socket错误，会弹出该条信息
        exit(1);
    }
    len=sizeof(server_addr);
    memset(&server_addr,0,len);//相当于用len个0填充server_addr
    server_addr.sin_family=AF_INET;//协议族
    server_addr.sin_addr.s_addr=inet_addr("127.0.0.1");//地址
    server_addr.sin_port=htons(7758);//端口
    memset(buf,0,100);
    if(connect(ssock,(struct sockaddr *)&server_addr,len)<0){
        perror("connect error");
        exit(1);
    }//连接
    int n;
    if((n=read(ssock,buf,100))<=0){
        perror("read error");
        exit(1);
    }//从ssock中读取100个字节到buf中
    if(write(ssock,client,100)<=0){
        perror("write error");
        exit(1);
    }//把client中的100个字节写入ssock
    buf[n]='';//字符串末尾加个结束符号
    close(ssock);//关闭
    printf("read :%s
",buf);//打印接收到的字符串
return 0;}

服务器端代码如下

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<sys/socket.h>
#include<arpa/inet.h>
#include<unistd.h>
#include<sys/stat.h>
int main(){
    int clen;
    int ssock,csock;
    struct sockaddr_in client_addr,server_addr;
    char buf[100]="this is from server";
    char cli[100];
    if((ssock=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP))<0){
        perror("socket error");
        exit(1);
    }
    clen=sizeof(client_addr);
    memset(&server_addr,0,sizeof(server_addr));
    server_addr.sin_family=AF_INET;
    server_addr.sin_addr.s_addr=htonl(INADDR_ANY);
    server_addr.sin_port=htons(7758);
    if(bind(ssock,(struct sockaddr *)&server_addr,sizeof(server_addr))<0){
        perror("bind error");
        exit(1);
    }
    if(listen(ssock,8)<0){
        perror("listen error");
        exit(1);
    }
    while(1){
        csock=accept(ssock,(struct sockaddr *)&client_addr,&clen);
        if(write(csock,buf,100)<=0)
            perror("write error");
        if(read(csock,cli,100)<=0){
            perror("read error");
        }
        else
            printf("from client %s
",cli);
        close(csock);
    }
    return 0;
}