Question

Consider the following procedures for string manipulation. Procedure Call Explanation concat(str1, str2) Returns a single string consisting of str1 followed by str2. For example, concat("key", "board") returns "keyboard". reverse(str) Returns the reverse of the string str. For example, reverse("abcd") returns "dcba". Which of the following code segments can be used to store "noon" in the string variable word ? word "no" word concat(reverse(word), word) Option A,word ← "no" word ← concat(reverse(word), word) A word "no" word concat(reverse(word), reverse(word)) Option B,word ← "no" word ← concat(reverse(word), reverse(word)) B word "on" word concat(reverse(word), word) Option C,word ← "on" word ← concat(reverse(word), word) C word "on" word concat(reverse(word), reverse(word))

Answer 1

Option C.

Starting with word ← "on", reverse(word) = "no" and concat(reverse(word), word) = "no" + "on" = "noon". The other options yield "onno", "onon", or "nono".