   how to input a value to a Variable in SDL
  in my programe,int a;  //Variableand while programe running ,there is a box ,i can press the keyboard,and show them in box at once,now,i wanna input a value with keybosrd to the a(Variable),how to do it?just as:int a = 1;when i press '2',then a = 2,and show '2' in the box at onceby the way :anybody explain SDL_WM_GrabInput() exactly? with a example the best!thank you!   
  can you explain a little bit further ?   