Study the following pseudocode that reverses the order of words in a sentence (not the characters). FUNCTION ReverseWords(Sentence : STRING) RETURNS STRING ...

(a) The word-extraction loop builds each word character by character until it hits a space, at which point the completed word is stored in the Words array: [3]

Processing "THE CAT SAT" character by character: T, H, E build CurrentWord = "THE". The space triggers storage into Words[1]. Then C, A, T build "CAT", the next space stores it in Words[2]. Finally S, A, T build "SAT", and the post-loop IF stores it in Words[3]. [1 mark for Words[1] and Words[2], 1 mark for Words[3], 1 mark for WordCount]

(b) The reversal loop starts from Words[3] and prepends each earlier word with a space separator. Result = Words[3] = "SAT", then "SAT" & " " & "CAT" = "SAT CAT", then "SAT CAT" & " " & "THE" = "SAT CAT THE". Return value: "SAT CAT THE". [1]

(c) The FOR loop only stores a word into the array when it encounters a space character. [1] The last word in the sentence is not followed by a space, so it would remain in CurrentWord without being added to the array. The IF check after the loop ensures this final word is also stored correctly. [1]

(d) For input "HELLO", there are no spaces, so the loop never triggers storage. The post-loop IF stores "HELLO" as Words[1] (WordCount = 1). The reversal starts with Result = Words[1] = "HELLO" and the FOR loop from 0 TO 1 STEP -1 does not execute. Return value: "HELLO". [1]

(e) A character-reversal function iterates from the end of the string to the beginning, appending each character to build the reversed result: [7]

FUNCTION ReverseChars(Text : STRING) RETURNS STRING
    DECLARE Result : STRING
    DECLARE i : INTEGER
    Result ← ""
    FOR i ← LENGTH(Text) TO 1 STEP -1
        Result ← Result & Text[i]
    NEXT i
    RETURN Result
ENDFUNCTION

[1 mark for loop from end to start, 1 mark for building result character by character, 1 mark for returning result]

(f) With input "THE CAT" (two spaces), the algorithm encounters the first space after "THE" and stores it in Words[1]. [1] When it encounters the second space, CurrentWord is empty (""). The IF check IF CurrentWord <> "" prevents this empty string from being added to the array, so the algorithm handles this correctly and produces the same result as single-spaced input. [1] Without this guard, an empty word would be stored, causing the reversed output to contain extra spacing. [1]

(g) Advantage 1: The function can be called multiple times from different parts of the program without rewriting the code (reusability). [1] Advantage 2: The function can be tested independently of the rest of the program, making debugging and maintenance easier (modularity). [1]

(h) The LENGTH function returns an INTEGER, because the number of characters in a string is always a whole number. [1]