unity3d - Unity C# Script Moving a character 2D -

i'm trying make script control character. want character move distance right while alternating left arrow , right arrow inputs. ideally when start game, press right arrow - character moves right 10px, press left arrow - character moves right , pattern continues on alternating , never allowing 2 of same inputs after eachother eg: left arrow left arrow or right arrow right arrow.

ended going this, :d

using unityengine; using system.collections;  public class playercontroller : monobehaviour {      public float movespeed;     public float jumpheight;     private keycode lasthitkey;      void start()     {     }      void update()     {         if(input.getkeydown (keycode.space))         {             getcomponent<rigidbody2d>().velocity = new vector2(0, jumpheight);         }           if(input.getkeydown (keycode.d))         {             if(lasthitkey == keycode.d)             {              }else             {                 getcomponent<rigidbody2d>().velocity = new vector2(movespeed, 0);                 lasthitkey = keycode.d;             }         }           if(input.getkeydown (keycode.a))         {             if(lasthitkey == keycode.a)             {              }else             {                 getcomponent<rigidbody2d>().velocity = new vector2(movespeed, 0);                 lasthitkey = keycode.a;             }         }     } }