C++ program for creation and traversal of a Binary Tree

#include<iostream.h>
#include<conio.h>
#include<process.h>
struct tree_node
{
tree_node *left;
tree_node *right;
int data;
} ;
class bst
{
tree_node *root;
public:
bst()
{
root=NULL;
}
int isempty() 
{
return(root==NULL);
}
void insert(int item);
void inordertrav();
void inorder(tree_node *);
void postordertrav();
void postorder(tree_node *);
void preordertrav();
void preorder(tree_node *);
};
void bst::insert(int item)
{
tree_node *p=new tree_node;
tree_node *parent;
p->data=item;
p->left=NULL;
p->right=NULL;
parent=NULL;
if(isempty())
root=p;
else
{
tree_node *ptr;
ptr=root;
while(ptr!=NULL)
{
parent=ptr;
if(item>ptr->data)		
ptr=ptr->right;
else
ptr=ptr->left;
}	
if(item<parent->data)
parent->left=p;
else
parent->right=p;
}
}
void bst::inordertrav()
{
inorder(root);
}
void bst::inorder(tree_node *ptr)
{
if(ptr!=NULL)
{
inorder(ptr->left);
cout<<"  "<<ptr->data<<"     ";
inorder(ptr->right);
}
}
void bst::postordertrav()
{
postorder(root);
}
void bst::postorder(tree_node *ptr)
{
if(ptr!=NULL)
{
postorder(ptr->left);
postorder(ptr->right);
cout<<"  "<<ptr->data<<"     ";
}
}
void bst::preordertrav()
{
preorder(root);
}
void bst::preorder(tree_node *ptr)
{
if(ptr!=NULL)
{
cout<<"  "<<ptr->data<<"     ";
preorder(ptr->left);
preorder(ptr->right);
}
}
void main()
{
bst b;
b.insert(52);
b.insert(25);
b.insert(50);
b.insert(15);
b.insert(40);
b.insert(45);
b.insert(20); cout<<"inorder"<<endl;
b.inordertrav();
cout<<endl<<"postorder"<<endl;
b.postordertrav();
cout<<endl<<"preorder"<<endl;
b.preordertrav();
getch();
}

#include<iostream.h> #include<conio.h> #include<process.h> struct tree_node { tree_node *left; tree_node *right; int data; } ; class bst { tree_node *root; public: bst() { root=NULL; } int isempty() { return(root==NULL); } void insert(int item); void inordertrav(); void inorder(tree_node *); void postordertrav(); void postorder(tree_node *); void preordertrav(); void preorder(tree_node *); }; void bst::insert(int item) { tree_node *p=new tree_node; tree_node *parent; p->data=item; p->left=NULL; p->right=NULL; parent=NULL; if(isempty()) root=p; else { tree_node *ptr; ptr=root; while(ptr!=NULL) { parent=ptr; if(item>ptr->data) ptr=ptr->right; else ptr=ptr->left; } if(item<parent->data) parent->left=p; else parent->right=p; } } void bst::inordertrav() { inorder(root); } void bst::inorder(tree_node *ptr) { if(ptr!=NULL) { inorder(ptr->left); cout<<" "<<ptr->data<<" "; inorder(ptr->right); } } void bst::postordertrav() { postorder(root); } void bst::postorder(tree_node *ptr) { if(ptr!=NULL) { postorder(ptr->left); postorder(ptr->right); cout<<" "<<ptr->data<<" "; } } void bst::preordertrav() { preorder(root); } void bst::preorder(tree_node *ptr) { if(ptr!=NULL) { cout<<" "<<ptr->data<<" "; preorder(ptr->left); preorder(ptr->right); } } void main() { bst b; b.insert(52); b.insert(25); b.insert(50); b.insert(15); b.insert(40); b.insert(45); b.insert(20); cout<<"inorder"<<endl; b.inordertrav(); cout<<endl<<"postorder"<<endl; b.postordertrav(); cout<<endl<<"preorder"<<endl; b.preordertrav(); getch(); }