The implementation of a linked list uses an integer variable and a 1D array List of type Node. Record type Node is declared in pseudocode as follows: TYPE Node DECLARE Data : STRING DECLARE Pointer : INTEGER ENDTYPE The array List is declared in pseudocode as follows: DECLARE List : ARRAY[1:200] OF Node The linked list will operate as follows: • Integer variable HeadPointer will store the array index for the first node in the linked list. • The Pointer field of a node contains the index value of the next array element (the next node) in the linked list. • The value 0 is used as a null pointer.

1. (a)(i)State why the value 0 has been selected as the null pointer.[1]
2. (a)(ii)Give the range of valid values that could be assigned to variable HeadPointer.[1]
3. (b)The array List will be initialised so that each node points to the following node. The last node will contain a null pointer. Complete the program flowchart to represent the algorithm for this operation. START[4]
4. (c)An algorithm outputs the Data field from all nodes in the array List. The order the Data is output should be the same order it is stored in the linked list. Describe the algorithm in four steps. Do not use pseudocode statements in your answer.[4]

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