Algorithms 1.2

Question 1

Object-oriented programming

Answer 1

Based on building data types

Question 2

Data type

Answer 2

A set of values and a set of operations on those values

Question 3

Abstract data type

Answer 3

a data type whose internal representation is hidden form the client

Question 4

Objects

Answer 4

an entity that can take on a data-type value

Question 5

Characterization of objects (3 properties)

Answer 5

1) State of an object- value from its data type
2) Identity of an object distinguishes one object from another
3) behavior of an object is the effect of data-type operations

Question 6

reference

Answer 6

a mechanism for accessing an object

Question 7

API

Answer 7

list of constructors and instance methods

Question 8

client

Answer 8

program that uses a data type

Question 9

implementation

Answer 9

the code that implenets the data type specified in an API

Question 10

Creating an object for a abstract data type

Answer 10

First, you must create an object my invoking a constructor ( new). Everytime a client uses new the system allocates memory space for the object, initializes its value and returns a reference to the object

Question 11

Invoking instance methods

Answer 11

e.g. heads.tally () - tails.tally

Question 12

Assignment Statements

Answer 12

A copy of a reference can be created. Leads to a situation called aliasing

Question 13

Objects as arguments

Answer 13

Objects can be used as arguments

Question 14

Objects as return values

Answer 14

An object can be used as a return value from a method

Question 15

Arrays are objects

Answer 15

Every value of any nonprimitive type is an object. E.g. arrays are objects

Question 16

Arrays of Objects

Answer 16

An array can also be filled with objects. Create by using the bracket syntax for array constructors and than create each object

Question 17

Constructors

Answer 17

establishes an object’s identity and initializes the instance variables

Question 18

Immutable

Answer 18

data type which has the property that the value of an object never changes. Accomplished using “final”

Question 19

Arithmetic Exception

Answer 19

Thrown when an exceptional arithmetic condition occurs

Question 20

ArrayIndexOutOfBoundsException

Answer 20

Thrown when an array is accessed with an illegal index

Question 21

NullPointerException

Answer 21

Thrown when null is used where an object is required

Question 22

OutOfMemoryError

Answer 22

Thrown when the java virtual machine cannot allocate an object because it is out of memory

Question 23

StackOverflowErrorw

Answer 23

Thrown when a recursive method recurs too deeply