avl_put.m

data structures C programs

function avl = avl_put(avl,data,key)

global avl_heightchange

avl_heightchange = 0;
avl=avl_put2(avl,data,key);



function avl=avl_put2(avl,data,key)

global bt_nil avl_heightchange avl_lh avl_eh avl_rh

current = avl;

if current == bt_nil
   node=pointer;	
	node.left=bt_nil;
   node.right=bt_nil;
   node.key=key;
   node.data=data;
   node.bf = avl_eh;
   avl_heightchange = 1;
   avl = node;
elseif key == current.key
   avl = current;
elseif key < current.key
   current.left = avl_put(current.left,data,key);
   if avl_heightchange == 1
      switch current.bf
      case avl_lh
         current = avl_bl(current);
         avl_heightchange = 0;
      case avl_eh
         current.bf = avl_lh;
      case avl_rh
         current.bf = avl_eh;
         avl_heightchange = 0;
      end
   end
   avl = current;
else
   current.right = avl_put(current.right,data,key);
   if avl_heightchange == 1
      switch current.bf
      case avl_lh
         current.bf = avl_eh;         
         avl_heightchange = 0;
      case avl_eh
         current.bf = avl_rh;
      case avl_rh
         current = avl_br(current);
         avl_heightchange = 0;
      end
   end
   avl = current; 
end