Chapter 5 : Method

Question 1

What are method used to?

Answer 1

1. Break a complex program into small, manageable pieces

public partial class Form1 : Form
{
private void myButton_Click(object sender, EventArgs e)
{
Method2();
}
private void Method2()
{
Statement
}

Question 2

What is the approach ( break a complex program into small, manageable pieces ) known as?

Answer 2

1. Divide & Conquer

Question 3

What is the general terms for breaking down a program to smaller units of code known as?

Answer 3

1. Modularization

Question 4

List out 2 parts for method definition

Answer 4

1. Header
2. body

Question 5

Where method header appears and indicate what?

Answer 5

1. Appears at the beginning of a method
2. Indicate access mode, return type, and method name

• private void DisplayMessage() {}

Question 6

What is the difference between a void method and a normal method?

Answer 6

1. void method does not return any value to the statement that called it

Question 7

What is a void method?

Answer 7

1. A method that simply executes the statement it contains and then terminates

Question 8

What is the method body?

Answer 8

1. Is a collection of statements that are performed when the method is executed

Question 9

List out the 4 parts of a method header

Answer 9

1. Access Modifier
2. Return Type
3. Method Name
4. Parameter ( Parentheses )

Question 10

What is the access modifier? What value is available?

Answer 10

1. Keywords that defines the access control
2. Value Available
   
   • private
   • public

Question 11

What is the difference between private and public method?

Answer 11

1. Access control ( private method can be called only by code inside the same class while public class can be called by code outside the class )

Question 12

What does return type specifies?

Answer 12

1. Specifies whether or not a method returns a value

• void - no return
  empty - return

Question 13

What is a method name?

Answer 13

1. The identifier of the method, it must be unique in a given program

• Like variable name

Question 14

What does a method’s name always followed by?

Answer 14

1. A pair of parentheses ()

Question 15

How to create and display a method?

Answer 15

private void goButton_Click(object sender, EventArgs e)
{
MessageBox.Show(“This is the goButton_Click method.”);
DisplayMessage();
}
private void DisplayMessage()
{
MessageBox.Show(“This is the DisplayMessage method.”);
}

Question 16

What is return point?

Answer 16

1. A memory address that the system saves to which it should return

Question 17

What will happen when the method ends?

Answer 17

1. The system jumps back to the return point and resumes execution

Question 18

What does the system needs to know when calling a method?

Answer 18

1. A system needs to know where the program should return after the method ends

Question 19

What techniques that the programmer commonly use to modularize a program?

Answer 19

1. Top-down design

Question 20

What does a top-down design does?

Answer 20

1. Breaks down an algorithm to methods

Question 21

List out the process for top-down design ( 3 )

Answer 21

1. The overall task that the program is to perform is broken down into a series of subtasks
2. Each subtask is examined to determine whether it can be further broken down into more subtasks
3. Once all subtasks have been identified, they are written in code

• Step 2 will be repeated until no more subtasks can be identified

Question 22

What is an argument?

Answer 22

1. Any piece of data that is passed into a method when the method is called

• MessageBox.Show(“Show”)

Question 23

What is a parameter?

Answer 23

1. A variable that receives an argument that is passed into a method

• private void DisplayValue (int value) {}

Question 24

What does string parameter accepts?

Answer 24

1. Only string arguments

Question 25

What does int parameter accepts?

Answer 25

1. Only int arguments
2. Cannot pass double or decimal arguments

Question 26

What does double parameter accepts?

Answer 26

1. double or int parameters
2. Cannot pass decimal value to double parameters

Question 27

What does decimal parameter accepts?

Answer 27

1. decimal , int parameters
2. Cannot pass double value to decimal parameters

Question 28

Can you pass more than one argument to a method?

Answer 28

1. Yes

Question 29

What is the syntax for named arguments?

Answer 29

1. parameterName : value

• Named Argument allows us to specify which prameter an argument should be passed into

private void showButton_Click(object sender, EventArgs e)
{
showName(lastName : “Smith”, firstName : “Suzanne”);
}

Question 30

What does Default Argument does?

Answer 30

1. Allow us to specify a default value when there isn’t arguements obtained by referencing the method

Question 31

How to write default arguments?

Answer 31

private void ShowTax(decimal price, decimal taxRate = 0.07m)
{
decimal tax = price * taxRate;
}

Question 32

What is a reference parameter?

Answer 32

1. A special type of parameter tht does not receive a copy of the argument’s value

• It becomes a reference to the argument that was passed into it

Question 33

How to write code for reference parameter?

Answer 33

private void SetToZero(ref int number)
{
number =0;
}

int myVar = 99;
SetToZero(ref myVar);

Question 34

What is the difference between an output parameter and reference parameter? ( 2 )

Answer 34

1. An argument doesn’t have to be a value before it is passed into an output parameter
2. A method that has an output must be the output parameter to some value before it finishes executing

Question 35

How to write code for Output Parameters?

Answer 35

private void SetToZero(out int number)
{
number = 0;
}

SetToZero(out myVar);

Question 36

What is a value returning method?

Answer 36

1. Is a method that returns a value to the part of the program that called it

Question 37

Why a value-returning method is like a void method ? ( 2 )

Answer 37

1. It contains a group of statements that performs a specific task
2. When I want to execute the method, I call it

Question 38

What statement will at the last of the statement of the method?

Answer 38

1. return statement

Question 39

How to write a return statement inside a method?

Answer 39

private int sum(int num1, int num2)
{
return num1 + num2;
}

Question 40

How to write code to return boolean values?

Answer 40

private bool IsEven(int number)
{
bool numberIsEven;
if (number % 2 == 0)
{
numberIsEven = true;
}
else
{
numberIsEven = false;
}
return numberIsEven;
}