Unit 3: Methods/Functions

Question 1

Define: Method

Answer 1

A collection of statements that are grouped together to perform an operation (e.g. main())

Question 2

True or False: In Java, a method is always defined inside a class

Answer 2

True

Question 3

Define: Pre-defined method

Answer 3

Methods already written and defined inside classes and provided by Java. Organized and stored in the standard packages (e.g. java.lang.Math)

Question 4

Define: Programmer-defined method

Answer 4

Programmer writes the method definition inside a class based on their requirement, if no pre-defined method is available. The method definition includes modifier(s), return type, method name, and types and number of parameters

Question 5

Why are methods useful?

Answer 5

A complex program can be broken down into sub tasks, each of which is easy to manage and implement (this is known as a modular programming approach)

Question 6

True or False: Generally, the driver class in Java contains static methods

Answer 6

True

Question 7

True or False: A method with a static modifier is not a static method

Answer 7

False

Question 8

True or False: A static method can only call a non-static method after creating an object of that class it belongs to

Answer 8

True

Question 9

True or False: In Java, a method can be defined inside another method and does not have to be defined as a separate entity

Answer 9

False

Question 10

Define: Void method

Answer 10

A method that does not return any value

Question 11

Define: Value-returning method

Answer 11

A method that returns a value using a return statement

Question 12

If a static method is called from a different class, it is done by using the ___________ followed by ___________

Answer 12

Name of the class, the dot (.) operator

Question 13

Define: Method signature

Answer 13

The combination of the method name (a valid identifier which can not be a keyword) and the data/object-types in the parameter list that contains formal parameters

Question 14

Define: Formal parameters

Answer 14

The variables declared in the method header

Question 15

Define: Actual parameters

Answer 15

Parameters involved in the method call line, there is no need to specify the datatype or method type in these parameters

Question 16

Define: Return-value type

Answer 16

The datatype of the value the method returns via a return-statement after it is done with the calculation

Question 17

True or False: A method can not return more than one object

Answer 17

True

Question 18

If a method does not return a value, the keyword ______ is used in place of return-value type

Answer 18

void

Question 19

When a method is called, the arguments must agree with the formal parameters in ____, _____________, and _______

Answer 19

Order, number of parameters, data types

Question 20

True or False: The variable names in the method header and in the arguments of the method-call can be different

Answer 20

True

Question 21

Define: Pass by value

Answer 21

When using a variable inside a method, any change to the value of the variable inside the called method does not change the original value in the calling method

Question 22

Define: Pass by reference value

Answer 22

When passing a reference-value of an object to a called method, the original value in the calling method can be changed from the called method

Question 23

Define: Stack (in RAM)

Answer 23

Stores local primitive variables (variables inside a program block), formal parameters, and local reference variables. Managed by the compiler in LIFO (Last in First out) basis

Question 24

Define: Heap (in RAM)

Answer 24

Stores dynamic/runtime variables; in Java, whenever we create any object, it is created in the heap space

Question 25

Define: Program code (in RAM)

Answer 25

Stores other program data not stored in heap or stack

Question 26

True or False: The parameter list contains all variables used by the method

Answer 26

False

Question 27

True or False: The following code is a valid definition for a method called “cube”:

public static double cube(double x) { //some code }

Answer 27

True

Question 28

Suppose your method does not return any value, could void be used as a return-value type?

Answer 28

Yes

Question 29

The signature of a method consists of _____ and ____

Answer 29

Method name, parameter list

Question 30

When you call a method with a parameter, the value in the argument is passed to the parameter. This is referred to as ________

Answer 30

Pass by value

Question 31

What will be the output of the method-call nPrint(‘a’, 4) for the method printChar() defined below:

public static void printChar(char ch, int n) {
System.out.print(ch);
n–;
}

Answer 31

a

Question 32

Breaking a program in to manageable-sized methods/procedures is called _______

Answer 32

Modular programming

Question 33

True or False: When a method is called, flow of control moves to the method’s header

Answer 33

True

Question 34

Define: Method overloading

Answer 34

If two or more method signatures have the same name but different parameter lists (in terms of datatypes, number of datatypes, or order of the datatypes), these methods are called overloaded methods, and this concept is known as method overloading

Question 35

Define: Ambiguous invocation

Answer 35

When there are two or more possible matches for a call of an overloaded function. This results in a compilation error

Question 36

What are some common mistakes in code writing with methods?

Answer 36

Misspelled method name in the method call or method header, calling a void method from the println() statement, no return statement for a non void method, returning a value from a void method, using datatypes in the method call, ambiguous invocation

Question 37

Define: Scope

Answer 37

The region of the program where an identifier can be used. It also provides the information about the lifetime of an identifier (the time during which an identifier actually has memory allocated to it)

Question 38

Define: Local scope (block scope)

Answer 38

Extends from the point of the variable/reference-variable declaration to the end of the block

Question 39

True or False: The variables/reference variables in Java can be accessed only within the block that declares it, and these variables are often called local variables

Answer 39

True

Question 40

True or False: If we want to use a modifier for a declared local variable or local reference-variable inside any method, other modifiers besides the “final” modifier can be used

Answer 40

False

Question 41

True or False: You can not declare a variable with the same name twice in the same code block or in a nested code block

Answer 41

True (compilation error will be generated)

Question 42

A __________ variable is defined inside the body of a method and is not accessible outside that method

Answer 42

Local

Question 43

Methods are ideal for use in menu-driven programs. When a user selects a menu item, the program can ______ the appropriate method to carry out the user’s choice

Answer 43

Call

Question 44

A method is executed when it is ______

Answer 44

Called

Question 45

The group of java statements in which an object/variable can be used is its __________

Answer 45

Scope