BST

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

typedef struct node
{
    int key;
    struct node *left;
    struct node *right;
}node;

node *creatnewnode(int key)
{
    node *n=(node*)malloc(sizeof(node));
    n->left=NULL;n->right=NULL;
    n->key=key;
    return n;
}


node *insert(node *root,int key)
{
    if(root==NULL){
        root=creatnewnode(key);
        return root;
    }
    else if(key<=root->key){
        root->left=insert(root->left,key);
    }
    else{
        root->right=insert(root->right,key);
    }
    return root;
}

void preorder(node *root)
{
    if(root==NULL) return;
    printf("%d ",root->key);
    if(root->left!=NULL) preorder(root->left);
    if(root->right!=NULL) preorder(root->right);
    return;
}

void inorder(node *root)
{
    if(root==NULL) return;
    if(root->left!=NULL) inorder(root->left);
    printf("%d ",root->key);
    if(root->right!=NULL) inorder(root->right);
    return;
}

void postorder(node *root)
{
    if (root==NULL)return;
    if(root->left!=NULL) postorder(root->left);
    if(root->right!=NULL) postorder(root->right);
    printf("%d ",root->key);
    return;
}


node *bstsearch(node *temp,int key)
{
    while(temp!=NULL){
        if(temp->key==key) return temp;
        if(key<=temp->key) temp=temp->left;
        else temp=temp->right;
    }
    return temp;
}


int main()
{
    node *root=NULL;
    node *temp=NULL;
    root=insert(root,5);
    root=insert(root,3);
    root=insert(root,7);
    root=insert(root,9);
    root=insert(root,4);
    preorder(root);
    printf("\n");
    postorder(root);
    printf("\n");
    inorder(root);
    printf("\n");
    temp=bstsearch(root,5);
    if(temp==NULL) printf("there is no value\n");
    else printf("There it is %d\n",temp->key);

    return 0;
}