绘制二叉树

public static<T>TNodeShadow buildShadowTree(TNode t,int level)
{
TNodeShadow newNode=null;
String str;
if(t!=null)
{
newNode=new TNodeShadow();
TNodeShadow newLeft=buildShadowTree(t.left,level+1);
newNode.left=newLeft;
str=(t.nodeValue).toString();
newNode.nodeValueStr=str;
newNode.level=level;
newNode.column=TNodeShadow.columnValue;
TNodeShadow.columnValue++;
TNodeShadow newRight=buildShadowTree(t.right,level+1);
newNode.right=newRight;
}
return newNode;
}

public static<T> String displayTree(TNode<T> t,int maxCharacter)
{
LinkedQueue<TNodeShadow> q=new LinkedQueue<TNodeShadow>();
String displayStr="";
int colWidth=maxCharacter+1;
int currLevel=0,currCol=0;
TNodeShadow.columnValue=0;
if(t==null)
return displayStr;
TNodeShadow shadowRoot=buildShadowTree(t,0);
TNodeShadow currNode;
q.push(shadowRoot);
while(!q.isEmpty())
{

currNode=q.pop();
if(currNode.level>currLevel)
{
currLevel=currNode.level;
currCol=0;
displayStr+='\n';
}
if(currNode.left!=null)
{
q.push(currNode.left);
}
if(currNode.right!=null)
{
q.push(currNode.right);
}
for(int i=0;i<currNode.column;i++)
{
displayStr+=' ';
}
displayStr+=currNode.nodeValueStr;
currCol++;
}
displayStr+="\n";
clearShadowTree(shadowRoot);
return displayStr;
}

public static<T> void clearShadowTree(TNodeShadow t)
{
if(t!=null)
{
clearShadowTree(t.left);
clearShadowTree(t.right);
t=null;
}
}