/*#include <errno.h>

#include <string.h>

#include <time.h>

#include <arpa/inet.h>

#include <unistd.h>*/

#include <stdlib.h>

#include<stdio.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <netinet/in.h>

#include <netdb.h>

/* TCP Tinh cac bieu thuc (client)*/

void error(char *msg)

{

    printf("%s

",msg);

    exit(1);

}

int main()

{

 char serverIP[20]="127.0.0.1";

 int portno=12345;

 int sockfd;

 struct sockaddr_in serv_addr;

 char buffer[256];

 int n,solan;

//solan = 0;

 //-------------------------------------

//while (solan < 3)

//{

 //------------------------------

 // Step 1: Create socket

 sockfd = socket(AF_INET, SOCK_STREAM, 0);

 if (sockfd < 0) error("ERROR opening socket");

 //-------------------------------

 // Step 2: Prepair Server Address Struct

 serv_addr.sin_family = AF_INET;

 serv_addr.sin_addr.s_addr=inet_addr(serverIP);

 serv_addr.sin_port = htons(portno);

 // Step 3: Connect to Server

 if (connect(sockfd,(struct sockaddr*)&serv_addr,sizeof(serv_addr)) < 0)

       error("ERROR connecting");

 printf("Connected to Server!

");

 //-------------------------------

 // Step 4: Send/Receive Data

      printf("Bai5: TCP Tinh cac bieu thuc

");

      printf("Day la client

");

      int a,b,kq;

      printf("[1] Tong 1+3+5+7+....+(2n+1)

");

      printf("[2] Tong 1*2 + 2*3+...+n*(n+1)

");

      printf("[3] Bieu thuc 1-2+3-4+..+(2n+1)

");

      printf("[4] Bieu thuc 1^2+2^2+3^2+4^2+..+n^2 (n>=0)

");

      printf("[5] Bieu thuc 1^3+2^3+3^3+4^3+..+n^3 (n>=0)

");

      printf("[6] Bieu thuc 1^2+3^2+5^2+..+(2n+1)^2 (n>=0)

");

      printf("[7] Bieu thuc 2^2+4^2+6^2+..+(2n)^2 (n>=0)

");

      printf("Chon bieu thuc can tinh: ");

      scanf("%d",&a);

      printf("Nhap n: ");

      scanf("%d",&b);

      send(sockfd, &a, sizeof(a),0);

      send(sockfd, &b, sizeof(b), 0);

      recv(sockfd, &kq, sizeof(kq),0);

      printf("Ket qua = %d

",kq);

 //---------------------------------

 // Step 5: Close Socket

      close(sockfd);

      return 0;

 }