C# 101

Question 1

What can I build with C#

Answer 1

A website, a console app, mobile, or AI

Question 2

How do you output a line of text in a Console App (with no variables)?

Answer 2

Console.WriteLine(“Hello World!”);

Question 3

What’s a Console App?

Answer 3

An command-line application that runs in the terminal window

Question 4

How do you declare a string Variable?

Answer 4

string aFriend = “Kendra”

Question 5

How would you output “Hello ____” using a string variable for the text to go in the blank?

Answer 5

string aFriend = “Scott”;

Console.WriteLine($”Hello {aFriend}”);

Question 6

At the end of each line you need a…

Answer 6

semicolon ;

Question 7

What is String Interpolation? Give an example.

Answer 7

Placing a variable between { and } characters to tell C# to replace that text with the value of the variable. Example:

string aFriend = “Scott”;
Console.WriteLine($”Hello {Scott}”);

Question 8

What is a String?

Answer 8

A group of characters strung together

Question 9

What character is really important when dealing with strings that contain variables?

Answer 9

The dollar sign ($), because it signals that the string to be output contains at least one variable.

Question 10

What will the output look like?

string greeting = “ Hello World! “;
Console.WriteLine($”{greeting}”);

string trimmedGreeting = greeting.TrimStart();
Console.WriteLine($”[{trimmedGreeting}]”);

trimmedGreeting = greeting.TrimEnd();
Console.WriteLine($”[{trimmedGreeting}]”);

trimmedGreeting = greeting.Trim();
Console.WriteLine($”[{trimmedGreeting}]”);

Answer 10

** Hello World! **
[Hello World! ]
[ Hello World!]
[Hello World!]

Question 11

What is an example of a String Method?

Answer 11

.TrimStart()

.Trim()

Question 12

What is an example of a Property?

Answer 12

.Length

Question 13

How do you run code in Visual Studio (hotkey)?

Answer 13

CTRL-F5

Question 14

How would you declare the following variables?
int
double
decimal

Answer 14

int a = 3;
double b = 3.0;
decimal c = 3.0M;

Question 15

What does the M in a decimal variable declaration represent?

Answer 15

The letter M was chosen as a visually-distinctive way to distinguish a decimal type from a double type.
I like to think of it as “deciMal”.

Question 16

How can you tell a Method from a Property in code?

Answer 16

A Method is followed by parentheses ()

A Property is not followed by parentheses

Question 17

The most common error I have made so far is…

Answer 17

Forgetting the semicolon;

Question 18

CTRL-Z will…

Answer 18

Undo

Question 19

Multi-line IF statements need….

Answer 19

Curly braces: { }

Question 20

To have VS format your code for you (indent, etc)…

Answer 20

First, Build the Solution, then run Code Cleanup
(was Format Document)
To do this, to to the bottom of the main window and click the dustbrush icon next to “no issues found”

Question 21

The == symbol…

Answer 21

…tests for equality

Question 22

The && symbol…

Answer 22

Represents “and”.

It means both conditions must be true to execute the statement in the True branch.

Question 23

The || symbol…

Answer 23

Represents “or”.

If either condition is true, the statement in the True branch will be executed.

Question 24

using System;

What does this mean?

Answer 24

The “using” statement imports a Library. This means that we have imported the System Library.

Console uses the System Library.

If you type “System.” you will see Methods and Properties appear after the dot. They are all part of the System Library.

Question 25

Namespace - what is it?

Answer 25

An envelope or package that is used to group and organize related Classes.

There are namespaces that already exist, and you can create your own namespaces.

• Built-In Namespace
• • Global Namespace
• ** Local Namespace

Question 26

What is a Class?

Answer 26

TBD

Question 27

static void Main(string[] args)

In this statement, what does “Main” mean?

Answer 27

The Main Method is is your first Method. It tells your computer that this is the entry point; this is where the program starts.

Question 28

static void Main(string[] args)

In this statement, what does “static” mean?

Answer 28

The Main method needs to be static (unchanging)

Question 29

static void Main(string[] args)

In this statement, what does “void” mean?

Answer 29

“void” indicates that the method returns nothing. All Methods in C# have to return something, so we use the term “void” to say that it returns nothing.

Question 30

static void Main(string[] args)

In this statement, what does “string[]args” mean?

Answer 30

“string[]” represents an unlimited array of arguments. The brackets represent an array. This tells the program to take these arguments and do something with them.