Completion of the mouseInfo function

The mouse_b function that is called twice in Listing 4:

Listing 4. Completion of the mouseInfo function. 
  //Test for a mouse button pressed. Set drawing color
  // based on left or right mouse button.
  if(mouse_b & 1){//left mouse button
    *color = makecol(255,0,0);//red
    return true;//signal the requirement to draw
  }else if(mouse_b & 2){//right button
    *color = makecol(0,255,0);//green
    return true;
  }else{//no button
    return false;//no drawing required
  }//end else
}//end mouseInfo