PF 101: C# Object-Oriented Programming Concepts

Method

A block of code which only runs when it is called.

Code Reusability

Define the code once, and can be used many times.

Access Modifiers

Keywords that are used in order to specify the accessibility of the methods.

Class Visibility: Public

Public members can be directly called once the object is created.

Class Visibility: Private

Private members called within a method and it is not visible when object is created.

Method Overloading

C# allows multiple methods to have the same name but with different signatures.

Static Methods

Can be called without creating an object of the class.

Optional Parameters

C# allows specifying default values for parameters, which makes them optional when calling the method.

Math Function: Round()

Rounds a number to the nearest integer or specified number of decimal places.

Math Function: Sqrt()

Returns the square root of a number.

Math Function: Pow()

Returns the value of x to the power of y.

Math Function: Abs()

Returns the absolute value of a number.

Length (String)

Gets the number of characters in a string.

String Manipulation: ToUpper() / ToLower()

Converts a string to upper or lower case format.

String Manipulation: Contains()

Checks if a string contains a specific substring.

String Manipulation: Replace()

Replaces all occurrences of a substring with another string.

String Manipulation: Substring()

Retrieves a portion of the string.

Array Functions: Length (Array)

Returns the number of elements in the array.

Array Functions: Sort()

Sorts the elements of an array in ascending order.

Array Functions: IndexOf()

Returns the index of the first occurrence of an element.

Type Convertion: ToInt32()

A static method provided by C# to convert a string to a 32-bit signed integer

Type Convertion: ToDouble()

Converts the value of the specified object to an double-precision floating-point number, using the specified culture-specific formatting information.

Type Convertion: ToString()

Returns a string that represents the object instance. Used to construct a string containing the information on an object that can be printed.

Type Convertion: Parse()

Converting a value from one data type (usually a string) to another type (like int , float , double , etc...)

This is common when working with user input, as data from Console.

Control Structures

A way to specify flow of control in any algorithm or program can be more clear and understood, it analyzes and chooses in which direction a program flows based on certain parameters or conditions

Sequential Logic

It follows a serial or a sequence flow.

Selection Logic

Allows one set of statements to be executed if a condition is true and another set of actions to be executed if a condition is false.

Iteration Logic

Employs a loop which involves a 'REPEAT Statement'.

For Loop (Iteration)

A for loop repeats a block of code a specific number of times or iterates over a collection of items (like lists or arrays).

While Loop

Repeats a block of code as long as a given condition is true. It is typically used when the number of iterations is not known in advance.

Encapsulation

The concept of bundling the data and methods that operate on the data within one unit.

Inheritance

The mechanism by which one class can inherit properties and methods from another class.

Polymorphism

The ability of an object to take on many forms.

Abstraction

The concept of hiding the complex reality while exposing only the necessary parts.

Object-Oriented Programming (OOP)

Programming paradigm based on objects and classes.

Classes

Containers for data attributes and methods.

Objects

Instances of classes containing specific data.

Constructors

Special methods invoked when class objects are created.

Type Casting

Assigning a value from one data type to another.

Implicit Casting

Automatically converting smaller types to larger types.

Explicit Casting

Manually converting larger types to smaller types.

Data Types

Classifications of data that determine storage size.

Operators

Symbols that perform operations on variables.

C#

Programming language used for Windows applications.

Comments

Annotations in code for clarity and explanation.

Exception Handling

Mechanism to handle runtime errors gracefully.

Try-Catch Method

Used to catch and handle exceptions in code.

Windows Forms

Framework for building Windows desktop applications.

Event-Driven Programming

Programming paradigm based on events and actions.

String

Variable containing a collection of characters.

Value Type

Data types holding values in their own memory.

Reference Type

Data types holding references to memory locations.

Overflowing

Condition when a calculation exceeds data type limits.

Identifiers

Names used to identify variables and functions.

Naming Convention

Rules for naming identifiers in programming.

Naming a Constructor

Constructors have the same name as the Class.

Implementing a Default Constructor

When you create a default constructor, you can SET an initial value of the class itself.

Copy Constructors

Constructors that copy itself.

Private Constructors

Preventing to implement this specific constructor, while implementing Encapsulation.

Static Constructor

You can only invoke this static Constructor...ONCE.

String Length

Find the length of the string 'Swim' Total char = 4.

Concatenating Strings

You can concatenate strings using the + operator.

String Interpolation

Using the '$' symbol before a string, allowing us to embed expression directly in a string.

String Methods

These methods help you manipulate and analyze string data.

String Comparison

Compare strings using methods like Equals, Compare, and CompareOrdinal for various types of string.

String Formatting

Using methods like 'string.Format' or interpolated strings for more complex formatting tasks.

Null vs. Empty Strings

Null string reference means the variable does not point to any string object, while an empty string is a valid string with no characters.

Variable

A name given to a storage location in memory. A data item whose value can change during the program's execution.

Constant

An immutable value. A data item whose value cannot change during a program execution.

Assignment Operator

Used to ASSIGN values to variables and to UPDATE the value of a variable.

Arithmetic Operator

Used to perform basic MATHEMATICAL OPERATIONS on numeric values.

Relational Operators

Used to COMPARE two values or expressions and return a boolean result.

Logical Operators

Used to PERFORM logical operations on Boolean values or expressions.

Expression

In C#: combination of operands (variables, literals, method calls) and operators that can be evaluated to a single value.

Camel Case

A naming convention where the first letter of the first word is lowercase and the first letter of each subsequent word is uppercase.

Pascal Case

A naming convention where the first letter of each word is capitalized.

Hungarian Notation

A naming convention that prefixes variable names with a type indicator.

Value Assignment

Can be assigned new values.

Scope

Determines where in the code variables can be accessed.

Lifetime

Duration during which a variable exists in memory.

Mutability

Whether a variable can be changed (mutable) or not (immutable).

Optional Parameters

C# allows specifying default values for parameters which make them optional when calling the method

Void

A return type that means this method doesn't have a return value

Spaghetti Codes

Program Jumps over the place and its difficult to follow

OOP Paradigm

Suggest that we should model Instructions in a Computer program with the data they manipulate and store these as components together

Procedural Programming

Sequence of Instructions to be executed.

Reference Datatype

Data types that contains a pointer to another memory

Initialization

giving a variable an initial value