Tukukkk

I'm new to c++ programming. I have a small excercise which enables the use of the following: using of windows socket programming, using of window api functions (CreateFile, ReadFile, and WriteFile), and using of seekg, seekp, tellg, and tellp functions.

Here's what's happening in my code,

1. Open a .txt file that has URLs inside (reddit.com,stackoverflow.com,google.com) and then read the URLs and put inside of strVal.




2. Then I split the value of the data inside of strVal using delimiter "," then the loop starts.




3. Then the windows socket programming will start.




4. Inside of the loop it will get the HTTP request of each URLs and will ask the request type(POST or GET).




5. Once the answer from the request was received, the data will be inside of Buffer.




6. Then I will open a .txt file to put the received request of the 3 domains.

Example here's the result of output.txt

The result is fine and the program is working on this part but for the last requirement of the program, they want me to change the order of the answered data inside of the .txt file using seekg, seekp, tellg, and tellp.

I tried to implement those functions and here's my code.

fstream fs0 ("C:\Documents and Settings\Administrator\My Documents\output.txt", ios::in | ios::out | ios::app);

ofstream fs1 ("C:\Documents and Settings\Administrator\My Documents\output1.txt", ios::out | ios::app);



//1st

fs0.seekg(2020, ios::beg);



char ab[2020];

fs0.read(ab, sizeof(ab));



//2nd

fs0.seekg(0, ios::cur);



char dc[2020];

fs0.read(dc, sizeof(dc));



//3rd 

fs0.seekg(0, ios::beg);



char abc[2000];

fs0.read(abc, sizeof(abc));



fs1.write(ab, sizeof(ab));

fs1.write(dc, sizeof(dc));

fs1.write(abc, sizeof(abc));



fs0.close();

fs1.close()

I just opened .txt file where the data inserted then just read the data using seekg then put it inside of a buffer then output. There's no sense because what if there's another domain inserted inside of the .txt file.

Now, my concern is on this part. Based on my code how can I change the order of the data inside of the txt file using seekg, seekp, tellg, and tellp?

Here's my overall code,

    int main()

    {

    //getting the data

    HANDLE openFile;

    //HANDLE openFile1;

    HANDLE putdataFile;

    BOOL rewriFile;

    //BOOL rewriFile1;

    char *strVal;

    //char *strVal1;



    char* point;

    //char* point1;

    DWORD dwNoBytetoRead = 0;

    //DWORD dwNoBytetoRead1 = 0;

    DWORD dwNoByteWritten = 0;

    char dataextracted = "C:\Documents and Settings\Administrator\My Documents";

    //40 dash

    string dash1 = "n--------------------";

    string dash2 = "--------------------n";



    //connecting to the server

    SOCKET Socket;

    SOCKADDR_IN SockAddr;

    struct hostent *host;

    char buffer[10000];

    int dataLen;

    int i = 0;

    //get

    string http1 = "GET / HTTP/1.1rnHost: ";

    string http2 = "rnConnection: closernrn";

    //post

    string http3 = "POST / HTTP/1.1rnHost: ";

    string http4 = "rnConnection: closernrn";

    //winsock startup

    WSAData wsaData;



    //1 or 2

    string input;



    //start of program.................................



    //open file

    openFile = CreateFile(L"C:\Documents and Settings\Administrator\My Documents\url.txt", GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);

    //allocating memory

    LARGE_INTEGER fs;

    GetFileSizeEx(openFile, &fs);

    unsigned long long fSize = fs.QuadPart;

    strVal = (char*) malloc (fSize + 1);

    memset(strVal, 0, fSize + 1);



    //reading the content

    rewriFile = ReadFile(openFile, strVal, fSize, &dwNoBytetoRead, NULL);

    cout << "The URL/s " << strVal << endl << endl;



    CloseHandle(openFile);



    //split string

    point = strtok(strVal, ",rn");



    while (point != NULL) {

    //get

    string httpRequestget = http1 + point + http2;

    //post

    string httpRequestpost = http3 + point + http4;

    //checking kung successful yung wsastartup

    if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) {

        cout << "WSAStartup failed.n";

        system("pause");

        //return 1;

    }



    //connects to domain

    Socket = socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);

        host = gethostbyname(point);



    SockAddr.sin_port=htons(80);

    SockAddr.sin_family=AF_INET;

    SockAddr.sin_addr.s_addr = *((unsigned long*)host->h_addr);



    //just to check kung connected or may error pala

      if(connect(Socket,(SOCKADDR*)(&SockAddr),sizeof(SockAddr)) != 0){

    cout << "Could not connect";

    system("pause");

    //return 1;

      }else{

      cout << "You are now connected to " << point << endl;

      }



    //choice 1 or 2

    cout << "Options to requestn";

    cout << "[1] HTTP request using GETn";

    cout << "[2] HTTP request using POSTn";

    cout << "Choose an option: ";

    cin >> input;

    cout << endl;



    if (input == "1"){

    // Sending a HTTP-GET-Request to the Web Server

    int sentBytes = send(Socket, httpRequestget.c_str(), strlen(httpRequestget.c_str()),0);

    } else if (input == "2") {

    // Sending a HTTP-POST-Request to the Web Server

    int sentBytes = send(Socket, httpRequestpost.c_str(), strlen(httpRequestpost.c_str()),0);

    }



    // Receiving and Displaying an answer from the Web Server

    ZeroMemory(buffer, sizeof(buffer));

    recv(Socket, buffer, sizeof(buffer), 0);



    //put data in a file

    putdataFile = CreateFile(L"C:\Documents and Settings\Administrator\My Documents\output.txt", FILE_APPEND_DATA, FILE_SHARE_WRITE, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);

    string dash3 = dash1 + point + dash2;

    //write dash

    rewriFile = WriteFile(putdataFile, dash3.c_str(), strlen(dash3.c_str()), &dwNoByteWritten, NULL);



    //write the content

    rewriFile = WriteFile(putdataFile, buffer, 2000, &dwNoByteWritten, NULL);



    CloseHandle(putdataFile);



    // Cleaning up Windows Socket Dependencies

     closesocket(Socket);

     WSACleanup();



        point = strtok(NULL, ",rn");



    }

    cout << endl << "Data is downloaded here: " << dataextracted << endl << endl;



    fstream fs0 ("C:\Documents and Settings\Administrator\My Documents\output.txt", ios::in | ios::out | ios::app);

    ofstream fs1 ("C:\Documents and Settings\Administrator\My Documents\output1.txt", ios::out | ios::app);



    //1st

    fs0.seekg(2020, ios::beg);



    char ab[2020];

    fs0.read(ab, sizeof(ab));



    //2nd

    fs0.seekg(0, ios::cur);



    char dc[2020];

    fs0.read(dc, sizeof(dc));



    //3rd 

    fs0.seekg(0, ios::beg);



    char abc[2000];

    fs0.read(abc, sizeof(abc));



    fs1.write(ab, sizeof(ab));

    fs1.write(dc, sizeof(dc));

    fs1.write(abc, sizeof(abc));



    fs0.close();

    fs1.close();

    system("pause");l



    return 0;

      }