client.cpp

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <netinet/in.h>
#include <netdb.h>
#include <memory.h>
#include <zconf.h>

void error(const char* msg){
    perror(msg);
    exit(0);
}

int main(int argc, char** argv){
    int sockfd;
    ssize_t n;
    uint16_t port;
    struct sockaddr_in serv_addr;
    struct hostent* server;
    char buffer[256];
    if(argc < 3){
        fprintf(stderr, "Uses %s hostname port", argv[0]);
        exit(0);
    }
    port = (uint16_t)atoi(argv[2]);
    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if(sockfd < 0){
        error("Unable to create socket");
    }
    server = gethostbyname(argv[1]);
    if(server == NULL){
        fprintf(stderr, "Np such host\n");
        exit(0);
    }
    bzero((char*)&serv_addr, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    bcopy(server->h_addr, (char*)&serv_addr.sin_addr.s_addr,
          (size_t)server->h_length);
    serv_addr.sin_port = htons(port);
    if(connect(sockfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr)) < 0){
        error("Error to connecting!!!");
    }
    printf("Please enter operation: ");
    bzero(buffer, 256);
    fgets(buffer, 255, stdin);
    n = write(sockfd, buffer, strlen(buffer));
    if(n < 0){
        error("Error to writing socket!!!");
    }
    bzero(buffer, 256);
    n = read(sockfd, buffer, 255);
    if(n < 0){
        error("Error reading from socket!!!");
    }
    printf("Result is = %s\n",  buffer);
    close(sockfd);
    return 0;
}