Cấu trúc dữ liệu: Cây nhị phân

#include <stdio.h>
#include <malloc.h>
typedef int DataType;
typedef struct Node{
    DataType Data;
    Node* Left;
    Node* Right;
};

typedef Node* Tree;

void MakeNullTree(Tree &T){
    T=NULL;
}
int EmptyTree(Tree T){
    return T==NULL;
}

Tree Create2(DataType V,Tree Left,Tree Right){
    Tree T = (Node*)malloc(sizeof(Node));
    T->Data = V;
    T->Left = Left;
    T->Right = Right;
    return T;
}
void PreOrder(Tree T){
    if (T!=NULL){
        printf("%d  ",T->Data);
        PreOrder(T->Left);
        PreOrder(T->Right);
    }
}
void InOrder(Tree T){
    if (T!=NULL){
        InOrder(T->Left);
        printf("%d  ",T->Data);
        InOrder(T->Right);
    }
}

void PostOrder(Tree T){
    if(T!=NULL){
        PostOrder(T->Left);
        PostOrder(T->Right);
        printf("%d  ",T->Data);
    }
}
int  IsLeaf(Tree T){
    return (T->Left==NULL && T->Right==NULL);
}
//dem so nut tren cay
int NbNodes(Tree T){
    if (T==NULL)
        return 0;
    else
        return 1+NbNodes(T->Left)+NbNodes(T->Right);
}
//dem so nut la tren cay
int NbLeaves(Tree T){
    if (T==NULL)
        return 0;
    else if (IsLeaf(T))
        return 1;
    else
        return NbLeaves(T->Left)+NbLeaves(T->Right);
}
int max (int a,int b){
    return (a>b)?a:b;
}
int Height(Tree T){
    if (T==NULL || IsLeaf(T))
        return 0;
    else
        return 1+max(Height(T->Left),Height(T->Right));
}
int main(){
    Tree T1=Create2(1,NULL,NULL);
    Tree T2=Create2(2,NULL,NULL);
    Tree T5=Create2(5,NULL,NULL);
    Tree T3=Create2(3,NULL,NULL);
    Tree T8=Create2(8,NULL,T2);
    Tree T12=Create2(12,T1,NULL);
    Tree T7=Create2(7,T5,T8);
    Tree T6=Create2(6,T3,T12);
    Tree T = Create2(9,T7,T6);
    printf("Duyet tien tu:\n");
    PreOrder(T);
    printf("\nDuyet trung tu:\n");
    InOrder(T);
    printf("\nDuyet hau tu:\n");
    PostOrder(T);
    printf("\nIsLeaf(8) = %d",IsLeaf(T8));
    printf("\nIsLeaf(1) = %d",IsLeaf(T1));
    printf("\nNbNodes(T) = %d",NbNodes(T));
    printf("\nNbLeaves(T) = %d",NbLeaves(T));
    printf("\nHeight(T) = %d",Height(T));
    return 0;
}