利用後續遍歷，遞迴實現

#include <stdio.h>
#include <stdlib.h>

typedef char ElementType;
typedef struct TNode *Position;
typedef Position BinTree;
struct TNode{
    ElementType Data;
    BinTree Left;
    BinTree Right;
};

BinTree CreatBinTree(); /* 實現細節忽略 */
int GetHeight( BinTree BT );

int main()
{
    BinTree BT = CreatBinTree();
    printf("%d\n", GetHeight(BT));
    return 0;
}

int GetHeight(BinTree BT)
{
	int hl, hr, max;
	if (BT != NULL)
	{
		hl = GetHeight(BT->Left);
		hr = GetHeight(BT->Right);
		max = hl > hr ? hl : hr;
		return (max + 1);

	}
	else
		return 0;
}