getSmallestNode

Short summary

finds the smallest node in a specified (sub)tree

Return: the node with the smallest value based on the comparedTo Method

• Return type: CNM_CollectionInterfaces.IBinaryTreeNode

Parameters

Name	Type	Comment	Kind
startNode	CNM_CollectionInterfaces.IBinaryTreeNode	the node from that the search should be started	input
nodebuffer	POINTER TO CNM_CollectionInterfaces.IBinaryTreeNode	-	inout
bufferindex	__XWORD	-	inout

Code

Declaration

METHOD PROTECTED getSmallestNode :CNM_CollectionInterfaces.IBinaryTreeNode
VAR_INPUT
	(*the node from that the search should be started*)
	startNode 				:CNM_CollectionInterfaces.IBinaryTreeNode;
END_VAR
VAR_IN_OUT
	nodebuffer				:POINTER TO CNM_CollectionInterfaces.IBinaryTreeNode;
	bufferindex				:__XWORD;
END_VAR
VAR
	currNode				:CNM_CollectionInterfaces.IBinaryTreeNode;
END_VAR
VAR CONSTANT 
	OBJECT_NOT_REFERENCED	:__XWORD := 0;
END_VAR

Implementation

IF THIS^.isObjectValid(startNode) THEN
	currNode := startNode;
	IF THIS^.isObjectValid(startNode.leftChild) THEN
		IF THIS^.isObjectValid(nodebuffer[bufferindex]) THEN
			inc(bufferindex);
		END_IF
		nodebuffer[bufferindex] := currNode;
		inc(bufferindex);
		currNode := currNode.leftChild;
	ELSE
		getSmallestNode := startNode;
		RETURN;
	END_IF
	WHILE THIS^.isObjectValid(currNode.leftChild) DO		
		nodebuffer[bufferindex] := currNode;
		currNode := currNode.leftChild;
		inc(bufferindex);
	END_WHILE
	dec(bufferindex);
	getSmallestNode := currNode;
	RETURN;
ELSE
	getSmallestNode := OBJECT_NOT_REFERENCED;
END_IF