Question

Consider the mystery method below: public static string mystery(string str1, string str2) { int index = str1.IndexOf(str2); return str1.Substring(index, index()); } What is true about the mystery method? A) The method finds the index of the first occurrence of str2 in str1. B) The method returns a substring of str1 starting from the index found. C) There is an error in the code. D) The method is incomplete; additional information is needed.

Answer 1

The mystery method attempts to find the index of str2 in str1 and return a substring from that index, but contains a coding error in its use of the Substring method.

Correct options are A, B and C.

Step-by-step explanation:

The mystery method in the question contains a piece of code that is intended to perform some string manipulation. The method takes two string parameters, str1 and str2, and it begins by finding the index of the first occurrence of str2 within str1. However, there is a mistake in the method implementation. The Substring method is incorrectly used, since the second argument is expected to be the length of the substring desired, but instead the method index() is mistakenly called. The correct usage of Substring would require two integers representing the starting index and the length of the substring. Thus, the correct answers to the question are A) The method finds the index of the first occurrence of str2 in str1, B) The method attempts to return a substring of str1 starting from the found index, and C) There is an error in the code.