(b) i) What is a queue? (2 marks) ii) Write the class interface for a node and for a queue using the predefined node in C++. (8 marks) (c) A linked list may be represented as follows: value next value xt value, next value next Head 15 19 25 30 mull The list starts with a pointer Head, which points to the first node and the next field of each node points to the next node. Diagrammatically show the steps i) to add a node at the beginning of the list. ii) to add a node at the end of the list. iii) to add a node in between two nodes. (6 marks)