| 1 |
| Handout B for e01 |
| CS56 F18 |
Useful Reference Items related to Sorting
Here are a few reminders of things we discussed in class, but that you might reasonably need a “reference” for if you were using them in the real world.
The interface java.util.Comparator<T> includes the following
method signature:
int |
compare(T o1, T o2) |
Compares its two arguments o1 and o2 for order. Returns a negative integer, zero, or a positive integer as the first argument is less than, equal to, or greater than the second. |
The interface java.lang.Comparable<T> includes the following
method signature:
int |
compareTo(T o) |
Compares this object with the specified object o for order. Returns a negative integer, zero, or a positive integer as this object is less than, equal to, or greater than the specified object. |
The class java.util.ArrayList<E> includes this method:
void |
sort(Comparator<? super E> c) |
Sorts this list according to the order induced by the specified Comparator. |
The class java.util.Collections contains the following static method:
static <T extends Comparable<? super T>> void |
sort(List<T> list) |
Sorts the specified list into ascending order, according to the natural ordering of its elements. |
The classes java.lang.String and java.lang.Double implement Comparable<String> and Comparable<Double>, each in the
way that you would expect.
Other potentially useful methods
In java.lang.Integer:
public static int |
compare(int i1, int i2) |
Compares the two specified int values. The sign of the int value returned matches the contract of the compare method in java.util.Comparator |
End of Handout