Server (GUI ... requests the transfer and receives the file.):

else if (LOWORD(wParam) == 7 &&
                HIWORD(wParam) == BN_CLICKED &&
                (HWND) lParam == downloadButton)
            { // when the download button is clicked it initiates the download...

                char location[501];
                char buffer[102400];
                char temp[101] = {"\0"};

                int selected = ListView_GetNextItem(fileBrowse,-1,LVNI_SELECTED);
                ListView_GetItemText(
                    fileBrowse,
                    selected,
                    0,
                    temp,
                    100
                ); //file name and location is taken from another field (i hope you don't need it as well...

                int length =  GetWindowTextLength (listFilesLocation) + 1;
                GetWindowText (listFilesLocation, location, length);
                strcat(location,temp);

                strcpy(buf,"downloadfile");
                send(client, buf, sizeof(buf), 0);
                strcpy(buf,location);
                send(client, buf, sizeof(buf), 0);

                char num[10];
                int fileSize = recv(client, num, sizeof(num), 0);
               // int fileSize = atoi(num);
                int count = 0;

                std::ofstream myfile;

                char myFile[100];
                strcpy(myFile,"C:\\theDownloads\\");
                strcat(myFile,temp);
                myfile.open (myFile, std::ios::out | std::ios::binary);
                if (myfile.is_open())
                {   
                    myfile.seekp (0, std::ios::beg);

                    while(count<fileSize)
                    {                  
                        count++;
                        recv(client, buffer, sizeof(buffer), 0);
                        myfile.write (buffer, sizeof(buffer));
                        Sleep(1);
                    }
                    myfile.close();
                }
                SendMessage(terminalWindow, LB_ADDSTRING, 0, (LPARAM) num);
                SendMessage(terminalWindow, LB_ADDSTRING, 0, (LPARAM) "File download complete\0");
                strcpy(buf,"EOR");
            }

Client (commandline porgram) ( waits for a request and sends the file to the server):

else if(!strcmp(buf,"downloadfile"))
        { //starts sending the file after it got the request "downloadfile"
            char filePath[256];
            char buffer[102400];
            recv(kSock, filePath, sizeof(filePath), 0);
            std::ifstream myfile;
            myfile.open (filePath, std::ios::in | std::ios::binary);
            if (myfile.is_open())
            {
                std::ifstream::pos_type size;
                char * memblock;
                myfile.seekg (0, std::ios::beg);
                int begin = myfile.tellg();
                myfile.seekg (0, std::ios::end);
                int end = myfile.tellg();
                size = (end - begin);
                myfile.seekg (0, std::ios::beg);
                int i=0;
                char num[10];
                itoa(size,num,10);
                send(kSock, num, sizeof(num), 0);
                strcpy(buf,"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0");
                while(i<size)
                {
                    i = i*102400;
                    myfile.read (buffer, sizeof(buffer));
                    send(kSock, buffer, sizeof(buffer), 0);
                    std::cout<<"Packet "<<i<<" sent: "<<sizeof(buffer)<<"\n";
                }
                delete[] memblock;
                myfile.close();
            }

            strcpy(buf,"EOR\0");
            send(kSock, buf, sizeof(buf), 0);
        }

Best regards!

best Regards!