Hello all! I'm doing a 3D simulation. Now I need something like variables in imperative languages. My mainLoop check for new events and renders scene. To use input for controling camera position I need variables. An equivalent code in C: void main_loop() { int loop_num = 0; bool run = 1; SDLEvent e; while(run) { while(SDL_PollEvent(&e)) { if(e.type == SDL_KeyDown) { if(... == SDLK_Left) camera_pos_x--; } else if ... ... } drawScene(); loop_num++; } } How to implement camera_pos_x, y and z as variables, which chage values in run? This is only simplified example, but it's important to implement it in as most imperative form as possible. Thank fo all answers. Matej 'Yin' Gagyi