test2

Class Utility2D

java.lang.Object

test2.Utility2D

public class Utility2D
extends Object

Method Summary

Modifier and Type	Method and Description
static List<Integer>	interval(int a, int b) Returns a list containing the elements [min, min + 1, min + 2, ..., max] where min is the smaller value of a and b, and max is the larger value of a and b.
static double	reciprocal(int x) Returns the double value equal to 1 divided by x.
static List<Integer>	zipper(List<Integer> s, List<Integer> t) Returns the zipper of two lists s and t without modifying s or t.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

reciprocal

public static double reciprocal(int x)

Returns the double value equal to 1 divided by x. For example,

 Utility2D.reciprocal(2)  returns 0.5
 

Parameters:

x - a value

Returns:

the quotient 1 divided by x

Throws:

ArithmeticException - if x is equal to zero

interval

public static List<Integer> interval(int a,
                                     int b)

Returns a list containing the elements [min, min + 1, min + 2, ..., max] where min is the smaller value of a and b, and max is the larger value of a and b. If a and b have the same value then the returned list contains only one element and that element is equal to a. For example:

 Utility2D.interval(-3, 2)  returns the list [-3, -2, -1, 0, 1, 2]
 

Parameters:

a - one end of an interval

b - the other end of an interval

Returns:

the list containing the elements [min, min + 1, min + 2, ..., max] where min is the smaller value of a and b, and max is the larger value of a and b

zipper

public static List<Integer> zipper(List<Integer> s,
                                   List<Integer> t)

Returns the zipper of two lists s and t without modifying s or t. The zipper of lists s and t is the list formed by alternating elements from s and t. The sizes of the lists can be different. Let the size of the shorter list be n; then the returned list is the zipper of the shorter list and the first n elements of the longer list, followed by the remaining elements of the longer list.

For example:

 s            t            Test2I.zipper(s, t)
 ---------------------------------------------
 [1]          [2]          [1, 2]
 [5, 7]       [6, 8]       [5, 6, 7, 8]
 [1, 1, 1]    [0, 0, 0]    [1, 0, 1, 0, 1, 0]
 []           [10, 9, 8]   [10, 9, 8]
 [-5, 7, 2]   [99]         [-5, 99, 7, 2]
 

Parameters:

s - a non-null list

t - a non-null list

Returns:

the zipper of the lists s and t