#include<stdio.h>
    #include<sys/types.h>
    #include<string.h>
    #include<stdlib.h>
    #include<sys/socket.h>
    #include<arpa/inet.h>
    #include<unistd.h>
    #define SA struct sockaddr
    #define LISTENQ 5
    int main(int argc,char**argv)
    {
    int fd,sockfd,listenfd,connfd;
    pid_t childpid;
    socklen_t client;
    struct sockaddr_in servaddr,cliaddr;
    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(atoi(argv[1]));
    bind(listenfd,(SA*)&servaddr,sizeof(servaddr));
    listen(listenfd,LISTENQ);
    client=sizeof(cliaddr);
    connfd=accept(listenfd,(SA*)&cliaddr,&client);
    char buffer[100];
    FILE *fp;
    read(connfd,buffer,100);
    fp=fopen("add1.txt","w");
    fprintf(fp,"%s",buffer);
    printf("the file was received successfully");
    printf("the new file created is add1.txt");
    }