Clicker

#include <windows.h>
#include <cstdio> // printf
#include <cstdlib> // atoi
#include <unistd.h> // getopt

bool KeyIsPressed ( unsigned char k )
{
    USHORT status = GetAsyncKeyState(k);
    return (((status & 0x8000) >> 15) == 1) || ((status & 1) == 1);
}

int click ( INPUT input, int sleep ) {
    input.mi.dwFlags = MOUSEEVENTF_LEFTDOWN;
    SendInput( 1, &input, sizeof( INPUT ) );

    ZeroMemory( &input, sizeof( INPUT ) );

    input.mi.dwFlags = MOUSEEVENTF_LEFTUP;
    SendInput( 1, &input, sizeof( INPUT ) );

    printf( "." );

    Sleep( sleep );

    return 0;
}

int click ( unsigned char key, bool toggle, int sleep ) {
    INPUT input;
    input.type = INPUT_MOUSE;

    while ( true ) {
        if ( toggle ) {
            while ( !KeyIsPressed( key ) ) {
                Sleep( 100 );
            }
            while ( KeyIsPressed( key ) ) {}
            while ( !KeyIsPressed( key ) ) {
                click( input, sleep );
            }
            while ( KeyIsPressed( key ) ) {}
        } else {
            while ( KeyIsPressed( key ) ) {
                click( input, sleep );
            }
        }

        Sleep( sleep );
    }

    return 0;
}

// Using main in favor of winmain to allow easier use of command line options
int __cdecl main( int argc, char *argv[] ) {
    char key    = 0x45;
    bool toggle = false;
    int sleep   = 10;
    int opt;

    while ( ( opt = getopt( argc, argv, "k:s:t" ) ) != -1 ) {
        switch (opt) {
            case 'k': // KEY
                key = optarg[0];
                if ( key > 0x60 && key < 0x7b ) {
                    key -= 0x20;
                }
                break;
            case 's': // SLEEP
                sleep = atoi( optarg );
                if ( sleep < 1) {
                    sleep = 1;
                }
                break;
            case 't': // TOGGLE
                toggle = true;
                break;
            default:
                break;
        }
    }

    printf( "Key:    %c\n", key);
    printf( "Toggle: %s\n", toggle ? "yes" : "no" );
    printf( "Sleep:  %i\n", sleep );

    click( key, toggle, sleep );

    return 0;
}