Clears the screen display.
CLS [ { 0 | 
      1 | 2 } ]` | 
Depending on the region of the screen you want to clear, CLS gives you four options.
| CLS | Clears text or graphics viewport | 
| CLS 0 | Clears the screen of all text and graphics | 
| CLS 1 | Clears only the graphics viewport | 
| CLS 2 | Clears only the text viewport, leaving the bottom line unchanged | 
CLS
This clears the screen.