C# Study Cards

Front 1

In C#, almost everything ...

Back 1

... can be treated as an object in this programming language.

Front 2

What are the differences between functions and variables in C# and those in JavaScript.

Back 2

In C# there are no global functions or global variables. Everything is in classes. JavaScript, however, does have global variables.

Front 3

A gaming system for which C# can do programming is

Back 3

The Xbox.

Front 4

A Namespace is?

Back 4

Just a collection of related classes.

Front 5

The general format for namespaces and classes is?

Back 5

Namespace.Class (e.g., System.Math).

Front 6

"Using" statements at the top of a program do what?

Back 6

Tell which pieces of the .NET framework library the project will be using.

Front 7

These "using" statements at the top of the .cs code are like what in JavaScript and C++?

Back 7

Like the import statements in javascript and C++.

Front 8

C# uses namespaces to do what?

Back 8

Organize code into related groups.

Front 9

Namespaces are an organizational tool that does what?

Back 9

Keep related code together.

Front 10

A NAMESPACE prevents certain problems. For example ...

Back 10

If your program defines a class with the same name as a class in some other .NET library (from MSFT or a third party), then THIS keeps keeps the two classes from interfering with one another.

Front 11

A C# program contains at least one what?

By default, IT is located where?

What does it consist of?

Back 11

A C# program contains at least one CLASS DEFINITION. By default, the class definition is immediately two lines down from the start of the namespace. It consists of the word "class" followed by another word. For example: "class Program" or "class XXX".

Front 12

The class keyword does what?

Back 12

The class keyword is used to define and create objects.

Front 13

Within your C# program, Visual Studio expects to find what in order to run at all?

Back 13

Within your C# program, Visual Studio expects to find a function named "Main". Main(){} is necessary for program to run. "Main" effectively starts your program.

Front 14

What is Console?

Back 14

"Console" is a built-in object in C#. You can use methods such as ".WriteLine" on it.

Front 15

How do built-in objects such as Console appear in the Visual Developer development window?

Back 15

Their letters appear blue-green. This is true of complex objects created by the programmer, as well.

Front 16

Under "Project" is an option to change ..

Back 16

... an option to change the major properties (essentially the settings) of your project.

Front 17

In properties, you can change ...

Back 17

... you can change the "Target Framework" (version of .NET) and the type of application (e.g., console).

Front 18

In project properties, you have options for changing ...

Back 18

... have options for changing "Application," "Build", "Debug" and others.

Front 19

Prefix increments and postfix increments matter when you are using ...

Back 19

... when you are using placeholder expressions. If you have a placeholder {0}, ++a will insert an incremented a into the placeholder. a++ will insert an UNincremented a into the placeholder.

Front 20

These types of operator help determine an object's type, and do so how?

Back 20

TYPE TESTING OPERATORS (becoming more like English). The "is" operator returns true is a variable IS a certain data type. The "as" operator converts a variable to another data type (if possible).

Front 21

What can compact if-else statements to single lines of code?

Back 21

TERNARY OPERATORS.

Front 22

You create a constant by ... Give an example.

Back 22

You create a constant by placing const before the data type of a variable. For example, "const int FREEZING = 32" You capitalize all letters in a constant. Using const prevents that variable from being changed anywhere else. Visual Studio allows for creation of universal constants.

Front 23

An enumeration does this ... for example ...

Back 23

An enumeration groups related constants together. For example, "const Temperatures {}"

Front 24

Enumerations have what be default?

Back 24

They have int data type by default.

Front 25

To change enumeration data type, use this form ...

Back 25

"enum Temperatures : datatype {}" (look this up in book)

Front 26

An enumeration is an object. Thus, if you type the name of that enumeration, such as "Temperatures", the text will turn green. With dot notation, you then can select of the constants it contains, e.g., "Tempreatures.FREEZING".

Back 26

An enumeration is an object. Thus, if you type the name of that enumeration, such as "Temperatures", the text will turn green. With dot notation, you then can select of the constants it contains, e.g., "Tempreatures.FREEZING".

Front 27

There are two main types of loops

Back 27

1) Loops that execute while a condition is met, and 2) Loops that execute a set number of times.

Front 28

Two special keywords for loops are ...

Back 28

Two special keywords for loops are break: (this means "leave the loop") and continue; (this means "return to the top of the loop code).

Front 29

"continue" means ...

Back 29

"continue" means, "don't read the rest of the code in this run of the loop, and return to the top of the loop as if you had completed one run."

Front 30

To declare a variable do the following ... optionally, you can ...

Back 30

To declare a variable, declare the variable data type and give the variable a name (e.g., int myAge;). Optionally, you can give a value when declaring a variable (int myAge = 28;).

Front 31

Put variables in what form?

Back 31

Put variables in camel case (first letter is lowercase). For example myAge, myFirstBirthday.

Front 32

In .NET, almost everything is ...

Back 32

an object.

Front 33

At the base of the .NET library is ... from it ...

Back 33

At the base of the .NET library is a base type called System.Object . From System.Object are derived call the other primitive data types (themselves classes), such as int, string, bool, char, decimal, etc.

Front 34

Int maps to ... "Int" is a shorthand way of saying, ... for char ...

Back 34

Int maps to System.Int32 . "Int" is a shorthand way of saying, "use the class System.Int32". Same for "System.Char." A char data type is actually a System.Char object. A "string" is an object (instance) derived from the System.String class.

Front 35

All primitive (built-in) data types are ...

Back 35

objects.

Front 36

Each instance of a data type is ...

Back 36

Each instance of a data type is an object. Thus, "int i = 0;" is an object. Note that int i = new int(); is equivalent to "int i = 0;"

Front 37

Note that all 15 built-in data types, since ... thus have ... (give example)

Back 37

Note that all 15 built-in data types, since they are objects, have built-in functions. (e.g., an instance of "int" has i.GetType();

Front 38

"int i = 0;" or "int i = new int();" has these two methods (among others).

Back 38

"int i = 0;" or "int i = new int();" has methods i.GetType(); and i.ToString(); and i.Equals(j);

Front 39

Keep in mind that "int" and "string" are aliases for ...

Back 39

Keep in mind that "int" and "string" are aliases for the data types "System.Int32" and "System.String"

Front 40

The function "int myFunction(object obj){ }" is doing what?

Back 40

That function is taking an object of class "System.Object" ("object" for short) and using it as an argument in myFunction, and is returning an object of data type "int".

Front 41

What is the Benefit of Almost Everything Being an Object?

Back 41

You can work with the 15 data types and all other objects in pretty much the same manner (e.g., using dot notation for methods/functions for all objects).

Front 42

In terms of numbers, computers use ... while humans use ...

Back 42

Computers use a base 2 number system (0-1), while humans use a base 10 number system (0-9).

Front 43

Numbers of type "decimal" naturally work with ...

Back 43

Numbers of type "decimal" naturally work with base 10 numbers, while numbers of type "double" naturally work with base 2 numbers (binary).

Front 44

"double" data type objects are up to ... times faster than ... data types.

Back 44

"double" data type objects are up to 10X faster than decimal data types.

Front 45

Unicode is ...

Back 45

... is an international standard for representing a wide number of characters from a wide number of languages.

Front 46

A string data type is ...

Back 46

This data type is just a series of unicode characters.

Front 47

To make a string literally (e.g., to make a string containing backslashes \ display the backslashes instead of treating backslashes as escape characters), simply do this ...

Back 47

... Simply precede the opening quotation mark of the strings with an @ symbol, as in: string myFilePath = @"myDocuments\photo.jpg".

Front 48

Can variables change?

Back 48

NO. Variables cannot change in C#. All you can do is create a new, altered variable. For example, string MyName = "Sean McGrorey" can only be used to create a new string, such as MyNewName = "Sean DeButts"

Front 49

Avoiding using ... to append to strings. Instead, ...

Back 49

Avoiding using "+=" to append to strings. Instead, create and use a StringBuilder object, and use its method. Creating a StringBuilder object is like creating a tool with functions. StringBuilder sb = new StringBuilder();

Front 50

A variable's "scope" essentially is...

Back 50

A variable's "scope" essentially is where it is visible. Effectively, where it exists as far as functionality is concerned.

Front 51

In a language such as C#, C, or Java, variables have what type of scope? What does this imply?

Back 51

In a language such as C#, variables have "block scope." A block of code is code within a set of braces. You also can nest scopes, just as you can next a pair of curly braces within another pair of curly braces (e.g., int myFunction(){int x = 1 {int y = 2}}

Front 52

In JavaScript, variables have what type of scope? What does this imply?

Back 52

In JavaScript, variables have function-level scope. There are no nested scopes within a JavaScript function. The interpreter goes through a function and lifts are variables to the top of the function

Front 53

C# does not allow you to do what with two different variables in different scopes?

Back 53

C# does not allow you to give declare two different variables with the same name in separate scopes.

Front 54

A class is ...

Back 54

A class is just a definition. It is not the object itself.

Front 55

Classes define two major things (called members) ...

Back 55

Classes define two major things (called members): 1) Fields: The kinds of data the objects holds. Think of all the fields (e.g., name, desription, DueDate) from your Database classes. 2) Methods, such as setDueDate(), convertToString();

Front 56

Classes can inherit ... from ...

Back 56

Classes can inherit attributes and methods from other classes.