Question

Which of the following String methods returns a negative value?

• A. length()
• B. equals()
• C. compareTo()
• D. charAt()

Hint:

Remember: \texttt{compareTo()} returns \textbf{negative}, \textbf{zero}, or \textbf{positive} depending on dictionary order of strings. It is commonly used for lexicographical comparison.

Answer 1

The Correct Option is C

Step 1: Understand what each String method returns.
In Java, different \texttt{String} methods return different types of values. Some methods return a number, some return a character, and some return a boolean value. To answer this question, we need to identify which method can return a negative integer value.
Step 2: Analyze each method one by one.

• (A) \texttt{length():} This method returns the number of characters in a string. Since the length of a string can never be negative, it does not return a negative value.
• (B) \texttt{equals():} This method compares two strings and returns either \texttt{true} or \texttt{false}. It does not return any numeric value.
• (C) \texttt{compareTo():} This method compares two strings lexicographically. It can return:
  • a negative value if the first string comes before the second string,
  • zero if both strings are equal,
  • a positive value if the first string comes after the second string.
  So, this method can definitely return a negative value.
• (D) \texttt{charAt():} This method returns the character present at a specified index in the string. It returns a character, not a negative number.

Step 3: Focus on \texttt{compareTo()}.
Suppose we compare: \[ \texttt{"Apple".compareTo("Banana")} \] Since \texttt{"Apple"} comes before \texttt{"Banana"} in dictionary order, the result will be a negative value. This shows clearly that \texttt{compareTo()} is the method that can return a negative value.
Step 4: Conclusion.
Therefore, among all the given String methods, the one that returns a negative value is \texttt{compareTo()}.
Final Answer:compareTo().