Program for BST

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

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

    struct node *newNode(int item)
    {
        struct node *temp =  (struct node *)malloc(sizeof(struct node));
        temp->key = item;
        temp->left = temp->right = NULL;
        return temp;
    }

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

    struct node* insert(struct node* node, int key)
    {
        if (node == NULL) return newNode(key);

        if (key < node->key)
            node->left  = insert(node->left, key);
        else
            node->right = insert(node->right, key);

        return node;
    }

    struct node * minValueNode(struct node* node)
    {
        struct node* current = node;

        while (current->left != NULL)
            current = current->left;

        return current;
    }

    struct node* deleteNode(struct node* root, int key)
    {
        struct node* temp;
        if (root == NULL) return root;

        if (key < root->key)
            root->left = deleteNode(root->left, key);

        else if (key > root->key)
            root->right = deleteNode(root->right, key);

        else
        {
            if (root->left == NULL)
            {
                struct node *temp = root->right;
                free(root);
                return temp;
            }
            else if (root->right == NULL)
            {
                struct node *temp = root->left;
                free(root);
                return temp;
            }

            temp = minValueNode(root->right);

            root->key = temp->key;

            root->right = deleteNode(root->right, temp->key);
        }
        return root;
    }

    void main()
    {
        struct node *root = NULL;
        root = insert(root, 50);
        root = insert(root, 30);
        root = insert(root, 20);
        root = insert(root, 40);
        root = insert(root, 70);
        root = insert(root, 60);
        root = insert(root, 80);

        printf("Inorder traversal of the given tree \n");
        inorder(root);

        printf("\nDelete 20\n");
        root = deleteNode(root, 20);
        printf("Inorder traversal of the modified tree \n");
        inorder(root);

        printf("\nDelete 30\n");
        root = deleteNode(root, 30);
        printf("Inorder traversal of the modified tree \n");
        inorder(root);

        printf("\nDelete 50\n");
        root = deleteNode(root, 50);
        printf("Inorder traversal of the modified tree \n");
        inorder(root);
        getch();
    }

Example