Tree

#include <stdio.h>
#include <stdlib.h>
//přidání, za/před konkrétní prvek, smazání prvku před/za, modifikace dat, vyvážení stromu
typedef struct t_Node {
    int key;
    struct t_Node *left;
    struct t_Node *right;
} t_Node_t;


t_Node_t *newNode(int item)         //creating new node
{
    t_Node_t *tmp = (t_Node_t *)malloc(sizeof(t_Node_t));

    tmp->key = item;

    tmp->left = tmp->right = NULL;

    return tmp;
}

void inord_trav(t_Node_t *root)     //inorder traversal w/recursion
{
    if(root != NULL) {
        inord_trav(root->left);
        printf("%d\n", root->key);
        inord_trav(root->right);
    }
}

t_Node_t *insert_key(t_Node_t *node, int given_key)      //inserting node with given data value
{
    if(node == NULL) {
        return newNode(given_key);
    }

    if(given_key < node->key) {
        node->left = insert_key(node->left, given_key);
    }
    else if(given_key > node->key) {
        node->right = insert_key(node->right, given_key);
    }

    return node;
}

t_Node_t *find_MinValue(t_Node_t *node)     //finding node with minimal value => topmost left leaf of the tree
{
    t_Node_t *current = node;

    while(current && current->left != NULL) {
        current = current->left;
    }

    return current;
}

t_Node_t *del_node(t_Node_t *root, int marker)
{
    if(root == NULL) {
        return root;
    }

    if(marker < root->key) {
        root->left = del_node(root->left, marker);
    }

    else if(marker > root->key) {
        root->right = del_node(root->right, marker);
    }

    else {
        if(root->left == NULL) {
            t_Node_t *tmp = root->right;
            free(root);
            root = NULL;
            return tmp;
        }

        else if(root->right == NULL) {
            t_Node_t *tmp = root->left;
            free(root);
            root = NULL;
            return tmp;
        }

        t_Node_t *tmp = find_MinValue(root->right);

        root->key = tmp->key;

        root->right = del_node(root->right, tmp->key);
    }

    return root;
}

int main()
{
    t_Node_t *root = NULL;

    //creating root
    root = insert_key(root, 50);

    //creating childs
    insert_key(root, 30);
    insert_key(root, 20);
    insert_key(root, 40);
    insert_key(root, 70);
    insert_key(root, 60);
    insert_key(root, 80);

    //print in inorder traversal
    printf("Inorder traversal of the given tree\n\n");
    inord_trav(root);

    //deleting 20
    printf("\nDelete 20\n");
    root = del_node(root, 20);
    printf("\nPrinting modified tree\n\n");
    inord_trav(root);

    //deleting 30
    printf("\nDelete 30\n");
    root = del_node(root, 30);
    printf("\nPrinting modified tree\n\n");
    inord_trav(root);


    return 0;
}