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@@ -11,3 +11,71 @@ up chain of nodes, we get a similarity to a linked list (O(n), n is the number
 of nodes).  Thus, the advantage of binary tree is lost. To correct this
 situation, tree balancing was created.  Advantages over a regular binary tree:
 insertion, deletion and search procedure for O(log n) even in the worst case.
+
+The algorithm is written in C based on some pseudocode fragments from the book
+"Introduction to algorithms" by Thomas H. Cormen.
+
+## Description
+
+This program performs demonstrates the capabilities of the rb algorithm.
+To do this, type in the command line of the terminal:
+
+```
+git clone https://git.scratko.xyz/red-black-tree
+cd red-black-tree
+make
+./red-black-tree
+```
+As seen in the second screenshot, the program displays an interactive menu.
+
+However, the algorithm can be used in other projects too. The `rb_tree.h` file
+provides a so-called API interface.  To take advantage of this, do the
+following: compile `rb_tree.c`
+
+```
+gcc -Wall -c rb_tree.c
+```
+
+You will receive `rb_tree.o` (object module).
+
+Thus, `rb_tree.h` is header file provides function declarations, and `rb_tree.o`
+is required for the final build of the executable file.
+
+Before using the functions, allocate dynamic memory in your program.
+
+```
+rb_tree \*new_tree = malloc(sizeof(rb_tree));
+```
+Do not forget to free the allocated memory at the end using:
+
+```
+free(new_tree);
+```
+
+
+## Interface for managing rb-tree
+
+1. *`void rb_tree_init(rb_tree \*t);`*
+
+To fill `new_tree` with initial values.
+
+2. *`node \*rb_tree_create_node(rb_tree \*t, int num);`*
+
+Returns a pointer of type `node\*` to the created node (note that the node has
+not yet been inserted into the tree). Or NULL if the num value has already been
+inserted into the tree.
+
+3. *`void rb_tree_insert_node(rb_tree \*t, node \*cur_node);`*
+
+4. *`void rb_tree_delete_node(rb_tree \*t, node \*cur_node);`*
+
+5. *`void rb_tree_clear(rb_tree \*t, node \*root);`*
+
+6. *`node\* rb_tree_search(rb_tree \*t, node \*root, int num);`*
+
+Returns a node of type `node\*`. If the value was not found into the tree, then the
+node will be equal to `t->nil`, otherwise it returns the node with the required value.
+
+7. `void rb_tree_print(rb_tree \*t, node \*root);`
+
+Displaying a binary tree in stdout.