LIQUID::LIQUID( bool& failed , SCREEN Screen_ ){

    if ( SDL_Init( SDL_INIT_EVERYTHING ) != -1 ) failed = false;
    else failed = true;

    Screen = Screen_;


    //LET THIS ALWAYS BE AT BOTTOM
    while(failed == false){



    }

}

Line 1: error: 'LIQUID' has not been declared
compilation terminated due to -Wfatal-errors.