Question

Hello, we are currently learning the compareTo() method in my Java Data Structures class. I am having trouble understanding what the output here will be:

a = "ballD";

b= "ballDs";

System.out.println(a.compareTo(b));

I don't know how to interpret the small "s". I know that if it was a = "ballD"; b = "ballD"; the output would be 0.

Please help, thanks in advance

Answer 1

If the first string is prefix of the second string then compareTo() returns negative of number of extra characters in string2.
If the second string is prefix of the first string then compareTo() returns number of extra characters in string2.

Example 1:
----------
a = "ballD";
b= "ballDs";
System.out.println(a.compareTo(b));
This prints -1
System.out.println(b.compareTo(a));
This prints 1

Example 2:
----------
a = "ballD";
b= "ballDst";
System.out.println(a.compareTo(b));
This prints -2
System.out.println(b.compareTo(a));
This prints 2

Example 3:
----------
a = "ballD";
b= "ballDstu";
System.out.println(a.compareTo(b));
This prints -3
System.out.println(b.compareTo(a));
This prints 3