binarySearchTree

#include <stdio.h>
#include <stdlib.h>
struct node{
    int data;
    struct node* rightl;
    struct node* leftl;
};
struct node* root=NULL;
struct node* parent=NULL;

int insert_data(){
    int item;
    printf("Enter data to be inserted:");
    scanf("%d",&item);
    return item;
}
void preorder(struct node* ptr){
    if(ptr!=NULL){
        printf("%d\t",ptr->data);
        preorder(ptr->leftl);
        preorder(ptr->rightl);
    }
}
void inorder(struct node* ptr){
    if(ptr!=NULL){
        inorder(ptr->leftl);
        printf("%d\t",ptr->data);
        inorder(ptr->rightl);
    }
}
void postorder(struct node* ptr){
    if(ptr!=NULL){
        postorder(ptr->leftl);
        postorder(ptr->rightl);
        printf("%d\t",ptr->data);
    }
}
struct node* search(int item){
    struct node* current=root;
    parent=NULL;
    while(current!=NULL){
        if(current->data==item){
            break;
        }
        else{
            parent=current;
            if(item>current->data)
                current=current->rightl;
            else
                current=current->leftl;
        }
    }
    return current;
}
void insertion(){
    struct node* current;
    struct node* newnode;
    newnode = (struct node*)malloc(sizeof(struct node));
    int item=newnode->data=insert_data();
    newnode->rightl=NULL;
    newnode->leftl=NULL;
    if(root==NULL)
        root=newnode;
    else{
        current=root;
        parent=NULL;
        while(current!=NULL){
            parent=current;
            if(item>current->data)
                current=current->rightl;
            else if(item<current->data)
                current=current->leftl;
            else{
                printf("Duplicate node");
                return;
            }
        }
        if(item>parent->data)
            parent->rightl=newnode;
        else
            parent->leftl=newnode;
    }
}
struct node* successor(struct node* temp){
    if(temp!=NULL){
        while(temp->leftl!=NULL)
            temp=temp->leftl;
    }
    return temp;
}
void deletion(int delItem){
    struct node* current;
    if(root==NULL){
        printf("Empty Tree\n");
        return;
    }
    current = search(delItem);
    if(current==NULL)
        printf("\nItem not Found!\n");
    else if(current->leftl==NULL && current->rightl==NULL){
        if(parent==NULL){
            free(current);
            root=NULL;
        }
        else if(parent->leftl==current){
            parent->leftl=NULL;
            free(current);
        }
        else if(parent->rightl==current){
            parent->rightl=NULL;
            free(current);
        }
    }
    else if(current->leftl==NULL && current->rightl!=NULL){
        if(parent==NULL){
            free(current);
            root=current->rightl;
        }
        else if(parent->leftl==current){
            parent->leftl=current->rightl;
            free(current);
        }
        else if(parent->rightl==current){
            parent->rightl=current->rightl;
            free(current);
        }
    }
    else if(current->leftl!=NULL && current->rightl==NULL){
        if(parent==NULL){
            free(current);
            root=current->leftl;
        }
        else if(parent->leftl==current){
            parent->leftl=current->leftl;
            free(current);
        }
        else if(parent->rightl==current){
            parent->rightl=current->leftl;
            free(current);
        }
    }
    else if(current->leftl!=NULL && current->rightl!=NULL){
        struct node* succ;
        succ=successor(current->rightl);
        delItem=succ->data;
        deletion(delItem);
        current->data=delItem;
    }
}
int main(){
    int arg;
    while(1){
        printf("\n******************");
        printf("\nEnter your choice:\n1. Insertion\n2. Traversal\n3. Deletion\n4. Search\n0. Exit");
        printf("\n******************\n");
        scanf("%d",&arg);
        switch(arg){
            case 1:
                insertion();
                break;
            case 2:{
                int search_arg;
                printf("\n*****_TRAVERSAL MENU_*****");
                printf("\nEnter your choice:\n1. PreOrder\n2. InOrder\n3. PostOrder");
                printf("\n**************************\n");
                scanf("%d",&search_arg);
                switch(search_arg){
                    case 1:
                        printf("\nPreOrder: ");
                        preorder(root);
                        break;
                    case 2:
                        printf("\nInOrder:   ");
                        inorder(root);
                        break;
                    case 3:
                        printf("\nPostOrder: ");
                        postorder(root);
                        break;
                }
                printf("\n");
                break;
            }
            case 3:{
                int item;
                printf("Enter item to be deleted:");
                scanf("%d",&item);
                deletion(item);
                break;
            }
            case 4:{
                int item;
                printf("Enter item to be searched: ");
                scanf("%d",&item);
                struct node* current=search(item);
                if(current==NULL)
                    printf("Item not Found");
                else
                    printf("Item Found");
                break;
            }
            case 0:
                exit(0);
            default:
                printf("Invalid Argument!");
                break;
        }
    }
}