Question

Suppose s1 and s2 are Strings and the following code is run:

s1 = s1.toLowerCase();
s2 = s2.toLowerCase();
System.out.println(s1.compareTo(s2));
If the code causes -25 to be output, which of the following must be true?

A. s1 appears before s2 alphabetically
B. s2 appears before s1 alphabetically

Answer 1

The output of -25 from the compareTo method indicates that s1 appears before s2 alphabetically after both strings are converted to lowercase.

Step-by-step explanation:

If the output of the System.out.println(s1.compareTo(s2)) is -25, this indicates that s1 appears before s2 alphabetically. The compareTo method in Java compares two strings lexicographically and returns a negative number if the first string (s1) comes before the second string (s2) alphabetically, zero if both strings are equal, and a positive number if s1 comes after s2.

In this case, since both strings have been converted to lowercase using s1.toLowerCase() and s2.toLowerCase(), we can conclude that s1 must start with a letter or sequence of letters that come before those that start s2 in the standard English alphabet. The magnitude of the number (-25) reflects the difference between the first non-matching characters in the two strings, based on their Unicode values.

When both strings are converted to lowercase using toLowerCase(), the characters are compared based on their ASCII values. Since the output is negative, it means that the ASCII value of the first different character in s1 is less than the corresponding character in s2.

For example, if s1 = 'apple' and s2 = 'banana', after converting to lowercase, the comparison would be 'apple' and 'banana'. The ASCII value of 'a' is 97 and the ASCII value of 'b' is 98. Since 97 is less than 98, s1 appears before s2 alphabetically.