Pausing the loop till keypress

[MewEight]

Are there anyways to pause the loop until either LCONTROL or RCONTROL is pressed?

Are there alternatives to stopping LCONTROL and RCONTROL increasing or decreasing counter by a huge sum?

#include <iostream>
#include <windows.h>
#include <conio.h>

using namespace std;

class Human{

    public:
        static int counter;

        Human(){
            counter++;
        }

        ~Human(){
            counter--;
        }
};

int Human::counter = 0;

int main()
{
    Human* h = new Human;

    bool isLeftControlPressed = false;
    bool isRightControlPressed = false;

    do{
        if(GetAsyncKeyState(VK_LCONTROL) && !isLeftControlPressed){
                h = new Human;
                isLeftControlPressed = true;
        }

        else if(!GetAsyncKeyState(VK_LCONTROL) && isLeftControlPressed){
                isLeftControlPressed = false;
        }

        if(GetAsyncKeyState(VK_RCONTROL) && !isRightControlPressed){
                delete h;
                isRightControlPressed = true;
        }

        else if(!GetAsyncKeyState(VK_RCONTROL) && isRightControlPressed){

                isRightControlPressed = false;
        }
        cout<<"Human Population : "<<Human::counter<<endl;

    }while(Human::counter > 0 && Human::counter < 10);

    if(Human::counter == 0){
        cout<<"\n\nWahahah No Human is alive!!\n";
    }

    else if(Human::counter == 10){
        cout<<"\n\nHumans Will Dominate!!\n";
    }

    return 0;
}

[JockX]

ReadConsoleInput() is probably the right choice here. It is a bit more complex, so make sure to read MSDN article and google for code examples.
http://msdn.microsoft.com/en-us/library/windows/desktop/ms684961%28v=vs.85%29.aspx

[MewEight]

What about the infinite printing of text? is there a way to print the text once then wait for input only printing a second time?

[JockX]

Make sure text is not displayed at each passing through the loop and only once per button press. Add bool alreadyPrinted = false; alongside other bools. Then change line 49 cout<<"Human Population : "<<Human::counter<<endl; to:

if (isRightControlPressed == false && isLeftControlPressed == false && 
    alreadyPrinted == true)
    alreadyPrinted = false;

if ((isRightControlPressed == true || isLeftControlPressed == true) 
    && alreadyPrinted == false)
{
    cout<<"Human Population : "<<Human::counter<<endl;
    alreadyPrinted = true;
}

[MewEight]

It worked brilliantly. Thanks, but i dont really get how to use the ReadConsoleInput() do you have any good examples?

[JockX]

Especially for you :D - a bit lenghty example I recovered from my old projects. It should compile as it is:

#include <iostream>
#include <Windows.h>
#include <string>

using namespace std;

void gotoxy( int x, int y )
{
    COORD c;
    c.X = x - 1;
    c.Y = y - 1;
    SetConsoleCursorPosition(GetStdHandle(STD_OUTPUT_HANDLE), c);
}

int main()
{

    cout << "\t\t\tPress LEFT ARROW or RIGHT ARROW. "
        << "\n\t\t\tTry typing some very long text. "
        << "\n\t\t\t\tPress ENTER to exit";

    // == These are needed for this input box in the middle, ignore them for now == //
    COORD prompt = {35, 11};
    gotoxy(prompt.X, prompt.Y);
    cout << "> ";
    HANDLE hConsole = GetStdHandle(STD_OUTPUT_HANDLE);
    CONSOLE_CURSOR_INFO CursorOn = { 100, true };
    SetConsoleCursorInfo(hConsole, &CursorOn); // Just makes cursor big
    int width = 10;
    char buffer[1] = "";
    string userInput = "";
    // ======================================================

    // This is relevant to you:
    // The key element to using ReadConsoleInput is this structure described here:
    // http://msdn.microsoft.com/en-us/library/windows/desktop/ms682079%28v=vs.85%29.aspx
    // This is where input events go to. Usually it's bigger than 1, 
    // but for simple console program one will do (need more if you want handle mouse too)
    INPUT_RECORD input[1];		
									
    // ReadConsoleInput returns number of events here, not very important for us
    DWORD NumberOfEventsRead;	

    // Think of it as of a pointer to Keyboard ;)
    HANDLE hKeyboard = GetStdHandle(STD_INPUT_HANDLE);

    while ( true )
    {
        ReadConsoleInput(hKeyboard, input, 1, &NumberOfEventsRead);
        if ( input[0].EventType == KEY_EVENT 
             && input[0].Event.KeyEvent.bKeyDown ) // If key was pressed
        {
            if (input[0].Event.KeyEvent.wVirtualKeyCode == VK_LEFT) 
            {
                gotoxy(1, 10);
                cout << "<=== HERE";
                gotoxy (70, 10);
                cout << "          ";
            }

            if (input[0].Event.KeyEvent.wVirtualKeyCode == VK_RIGHT)
            {
                gotoxy(70, 10);
                cout << "THERE ===>";
                gotoxy (1, 10);
                cout << "         ";
            }
			
            /* 
            Do not get into the rest of the code for now...
            I should really use sth like
					
                    swith (input[0].Event.KeyEvent.wVirtualKeyCode) 
                    {
                        case VK_LEFT:
                        case VK_RIGHT:
                        etc..
                    }
			
             here, but it's old, and I don't feel like
             rewriting it and messing with working code
             */

            string::iterator end = userInput.end(); // Retrieve the character that was pressed.
            buffer[0] = input[0].Event.KeyEvent.uChar.AsciiChar;
            if ( buffer[0] == 13 ) // enter pressed
            { 
                gotoxy(prompt.X, prompt.Y);
                for (size_t i = 0; i < width; i++)
                    cout << ' ';
                gotoxy(prompt.X, prompt.Y); // cleanup
                break;
            }

            if ( buffer[0] == 8 ) // backspace
            { 
                if ( userInput.size() > 0 )
                    userInput.erase(end - 1);
            }
			
			// 0 is function keys, shift, ctrl, etc, 27 is Esc '<-', 09 is Tab "->"
            else if ( buffer[0] != 0 && buffer[0] != 27 && buffer[0] != '\t' )
            { 
                userInput += buffer[0];
            }

            gotoxy(prompt.X, prompt.Y);
            cout << "> ";
            if ( static_cast<short>(userInput.size()) < width - 2 )
            {
                cout << userInput;
                for (size_t i = userInput.size() + 2; i < width; i++) //black-out rest of the line
                    cout << ' ';
                gotoxy(prompt.X + userInput.size() + 2, prompt.Y);
            }

            else
            {
                cout
                << userInput.substr(userInput.size() - width + 2,
                                    userInput.size());
                gotoxy(prompt.X + width - 1, prompt.Y);
            }
        }
    }

	gotoxy (1, 23);
	cout << "You have written: " << userInput << endl << endl; 
	system ("pause");
}

[MewEight]

Thanks. Will give it a try to understand, thanks for the help!