Methods

Question 1

public static void main (String []args)

Identify the parts of the method.

Answer 1

void - return type
main - method name
(String []args) - parameter

Question 2

What is the format of a method?

Answer 2

public static return_type methodName ([parameters])

Question 3

It is a variable that will receive the value being passed in calling the method.

Answer 3

Parameters

Question 4

This return type will not return any value.

Answer 4

void

Question 5

a collection of statements that are grouped together to perform an operation.

Answer 5

Method

Question 6

a collection of statements that are grouped together to perform an operation.

Answer 6

Method

Question 7

Examples of defined methods in the Java library

Answer 7

• System.out.println
• Integer.parseInt,
• Double.parseDouble
• System.exit
• Math.pow
• Math.random.

Question 8

Syntax in declaring method

Answer 8

[accesskeyword] static returntype methodname (parameter) {
}

Question 9

can be public, private, or protected.

Answer 9

Access keyword

Question 10

What will be the default form of access if no access modifier is declared?

Answer 10

Package

Question 11

indicates the type of value returned or reported back to the calling method, and it is most often used in conjunction with the assignment of a value to a variable in the calling method.

Answer 11

Return type

Question 12

What can the return type be?

Answer 12

• any Java primitive data type
• an object
• void

Question 13

This return type denotes hat the method has no return value

Answer 13

Void

Question 14

What naming rules does the method name follow?

Answer 14

Follows the same naming rules as variables and will generally begin with a lowercase letter.

Question 15

What are methods and variables caused because they are both contained inside classes?

Answer 15

They are called class members

Question 16

receives the value being passed when a function is called

Answer 16

Parameter

Question 17

What is used to separate parameters in a parameter list?

Answer 17

Comma

Question 18

states the data type of the parameter, which can be either a primitive data type or an object.

Answer 18

First entry in a parameter

Question 19

declares the name to be used when referencing the parameter within the method.

Answer 19

Second entry in a parameter

Question 20

a variable inside the method

Answer 20

Parameter

Question 21

Name the parts of the method
public static int max(int num1, int num2)

Answer 21

public static int max(int num1, int num2) - method header
public - access keyword
static - modifier
int - returntype
max - method name
(int num1, int num2) - parameter list
num1 & num2 - parameter

Question 22

What would the output be?
public static void main(String[] args) {
System.out.println(“Main Methods”);
DisplayMessage();
System.out.println(“Back to Main Methods”);
}

static void DisplayMessage(){
System.out.println(“Programming is great fun!”);
}

Answer 22

Main Methods
Programming is great fun!
Back to Main Methods

Question 23

What would the output be?
public static void main(String[] args) {
DisplayNumbers();
DisplayMessage();
}

static void DisplayMessage(){ 
	System.out.println("Programming is great fun!");
}

static void DisplayNumbers(){ 
	System.out.println("One");
	System.out.println("Two");
	System.out.println("Three");
}

Answer 23

One
Two
Three
Programming is great fun!

Question 24

TRUE OR FALSE: Methods can also be called in a hierarchical, or layered fashion.

Answer 24

TRUE

Question 25

What would the output be?
public static void main(String[] args) {
DisplayMessage();
DisplayNumbers();
}

static void DisplayMessage(){
System.out.println(“Programming is great fun!”);
Looping();
}

static void DisplayNumbers(){
System.out.println(“One”);
System.out.println(“Two”);
System.out.println(“Three”);
}

static void Looping(){
for (int x=1; x<=5; x++)
System.out.println(x + “ “);
}

Answer 25

Programming is great fun!
1 2 3 4 5
One
Two
Three

Question 26

TRUE OR FALSE: A method may be written so it accepts arguments. Data can then be passed into the method when it is called.

Answer 26

TRUE

Question 27

Values that are sent into a method

Answer 27

Arguments

Question 28

a special variable that holds a value being passed into a method.

Answer 28

Parameter variable

Question 29

What would the output be?
public static void main(String[] args) {
DisplayNumber(5);
}

static void DisplayNumber(int num){ 
	System.out.println("The value is " + num);
}

Answer 29

The value is 5

Question 30

What would the output be?
public static void main(String[] args) {
int a=3, b = 4;
DisplayNumber(5);
DisplayNumber(4 * 3-1);
DisplayNumber(a * 2);
DisplayNumber(a+b);
}

static void DisplayNumber(int num){
System.out.println(“The value is “ + num);
}

Answer 30

The value is 5
The value is 11
The value is 6
The value is 7

Question 31

What would the output be?
public static void main(String[] args) {
ShowNum(23.4, 45.7);
}

static void ShowNum(double num1, double num2){
double sum= num1 + num2;
System.out.println(“Num1 : “ + num1);
System.out.println(“Num2 : “ + num2);
System.out.println(“The sum is “ + sum);
}

Answer 31

Num1 : 23.4
Num2 : 45.7
The sum is 69.1

Question 32

TRUE OR FALSE: Each parameter variable in a parameter list doesn’t need to have a data type listed before its name.

Answer 32

FALSE, a compiler error would occur if not all of the parameter variables doesn’t have a data type listed before its name

Question 33

declared inside a method and is not accessible to statements outside the method.

Answer 33

Local Variables

Question 34

Can different methods can have local variables with the same names?

Answer 34

Yes, because the methods cannot see each other’s local variables

Question 35

Identify the local variables and method parameters.
public static void main(String[] args) {
int x, y;
}

static void ShowNum(double num1, double num2){
int sum;
}

static void FindProduct(double number){
int product, square;
}

Answer 35

main
local variables - x, y
method parameter - args
ShowNum
local variables - sum
method parameter - num1, num2
FindProduct
local variables - number
method parameter - Product, square

Question 36

are not automatically initialized with a default value. They must be given a value before they can be used.

Answer 36

Local variables

Question 37

What happens if you use a local variable before it has been given a value?

Answer 37

A compilor error will result

Question 38

What would the output be?
public static void main(String[] args) {
int x=5;
System.out.println(“Before Calling ChangeValue Method: “ + x);
ChangeValue(x);
System.out.println(“Before Calling ChangeValue Method: “ + x);
}

static void ChangeValue(int x){
x=50;
System.out.println(“Inside ChangeValue Method: “ + x);
}

Answer 38

The value of the local value is not affected when the value of variable is changed in other method.
Before Calling ChangeValue Method: 5
Inside ChangeValue Method: 50
Before Calling ChangeValue Method: 5

Question 39

A method may send a value back to the statement that called the method. Data may be passed into a method by way of parameter variables. Data may also be returned from a method, back to the statement that called it.

Answer 39

Returning a value from a method

Question 40

These are methods that return a value

Answer 40

Value-returning methods

Question 41

Explain what happens to the variables and the output.
public static void main(String[] args) {
int total = GetSum(10,20);
System.out.println(“Total: “ + total);
}

static int GetSum(int num1, int num2){
int sum = num1+num2;
return sum ;
}

Answer 41

VARIABLE TRACING
num1=10
num2=20
sum=num1+num2 | sum=30
total=sum | total=30
OUTPUT
Total:30

Question 42

TRUE OR FALSE: The non void value must return any value otherwise it would be a compilation error

Answer 42

TRUE

Question 43

Why does an error occur if you put a statement after the return statement?

Answer 43

Because the statement after the return statement is a dead code or unreachable statement