Binary Tree

/* A menu driven program for binary search tree creation and inorder,
   preorder,postorder recursive traversals of all nodes.Modify the program
   for performing following operations:
   (a) Search a value (b) Insertion of a value
*/

#include<stdio.h>
#include<stdlib.h>
typedef struct BSTnode
{
int data;
struct BSTnode *left,*right;
}BSTnode;

BSTnode *find(BSTnode *,int);
BSTnode *insert(BSTnode *,int);
BSTnode *create();
void inorder(BSTnode *T);
void preorder(BSTnode *T);
void postorder(BSTnode *T)

int main()
{
BSTnode *root=NULL,*p;
int x,op;
do
 { printf("\n\n1)Create\n2)Insert\n3)Search\n4)Preorder(recursive)");
   printf("\n5)Inorder(recursive)\n6)Posorder(Recursive)");
   printf("\n7)Quit");
   printf("\nEnter Your Choice :");
   scanf("%d",&op);
    switch(op)
     {
case 1: root=create();break;
case 2: printf("\nEnter the key to be inserted :");
scanf("%d",&x);
root=insert(root,x);
break;
case 3: printf("\nEnter the key to be searched :");
scanf("%d",&x);
p=find(root,x);
if(p==NULL)
 printf("\n ***** Not Found****");
else
 printf("\n ***** Found*****");
break;
case 4: preorder(root);break;
case 5: inorder(root);break;
case 6: postorder(root);break;

    }
}while(op!=7);
}


void inorder(BSTnode *T)
{
if(T!=NULL)
{
inorder(T->left);
printf("%d\t",T->data);
inorder(T->right);
}
}

void preorder(BSTnode *T)
 {     if(T!=NULL)
 { printf("%d\t",T->data);
   preorder(T->left);
   preorder(T->right);
 }
 }
void postorder(BSTnode *T)
 {     if(T!=NULL)
 {
   postorder(T->left);
   postorder(T->right);
   printf("%d\t",T->data);
 }
 }

BSTnode *find(BSTnode *root,int x)
{
while(root!=NULL)
{
if(x==root->data)
return(root);
if(x>root->data)
root=root->right;
else
root=root->left;
}
return(NULL);
}

BSTnode *insert(BSTnode *T,int x)
{
BSTnode *r;
// acquire memory for the new node
if(T==NULL)
 {
r=(BSTnode*)malloc(sizeof(BSTnode));
r->data=x;
r->left=NULL;
r->right=NULL;
return(r);
 }


if(x>T->data)
 {
T->right=insert(T->right,x);
return(T);
 }
else
if(x<T->data)
 {
T->left=insert(T->left,x);
return(T);
 }
else //duplicate data
return(T);
 }

BSTnode *create()
{
int n,x,i;
BSTnode *root;
root=NULL;
printf("\nEnter no. of nodes :");
scanf("%d",&n);
printf("\nEnter tree values :");
for(i=0;i<n;i++)
{
scanf("%d",&x);
root=insert(root,x);
}
return(root);
}