typedef struct  node

{

node *left,right; 

int data;

} node;

// Khai báo kiểu con trỏ chỉ đến nút

typedef struct node *tree;

Khởi tạo cây rỗng

void CreateTree(tree &t)

 {

t=NULL;

}

Kiểm tra cây có bị rỗng không

bool EmptyTree(tree t)

{

return ( t == NULL);

}

tree SearchTree(tree t, int x)

{

if(x<t->data)

SearchTree(t->left,x);

else if(x>t->data)

SearchTree(t->right,x);

else

return t;

}

void InsertTree(tree &t, int x)

{

if(t==NULL) // !EmptyTree(t)

{

t = (tree) malloc(sizeof(node));

t->data = x;

t->left = NULL;

t->right = NULL;

}

else if(x<t->data)

InsertTree(t->left,x);

else

InsertTree(t->right,x);

} 

void Del (tree &p, tree &q)

{if(p->right !=NULL)

Del(p->right,q);

else

{q->data = p->data;

q = p;

p = q->left;

}

}

gia su xoa nut 10

void DeleteTree (tree &t, int x)

{

tree q;

if( x<t->data )

DeleteTree(t->left,x);

else if ( x>t->data)

DeleteTree(t->right,x);

else

{

q = t;

if (t ->right = = NULL)t = t ->left;else if (t->left == NULL)

t = t ->right;else

Del(t->left,q) ;

free (q);

}

}

void LNR(tree t,int muc)

{

cout<<endl;

if(t!=NULL)

{

muc++;

LNR(t->left,muc);

cout<<setw(muc*5)<<t->data;

LNR(t->right,muc);

muc--;

}

}

void LRN(tree t,int muc)

{

cout<<endl;

if(t!=NULL)

{

muc++;

LRN(t->left,muc);

LRN(t->right,muc);

muc--;

cout<<setw(muc*5)<<t->data;

}

}

void NLR(tree t,int muc)

{

cout<<endl;

if(t!=NULL)

{

cout<<setw(muc*5)<<t->data;muc++;

NLR(t->left,muc);

NLR(t->right,muc);

muc--;

}

}