August 5, 2024

Class

In C#, a class is a user-defined blueprint or prototype from which objects are created. It represents a group of related properties and methods that define the behavior of the objects.

Structure of a C# Class

A C# class typically consists of:

1. Fields: Variables that hold data.
2. Properties: Accessors for fields.
3. Methods: Functions that define behavior.
4. Constructors: Special methods for initializing objects.
5. Events: Notifications sent by an object.

Object

In C#, an object is an instance of a class. When a class is defined, no memory is allocated until an object of that class is created. An object is a real-world entity, like a car, house, or employee, that has state and behavior. The class defines the properties (state) and methods (behavior) that the objects created from the class will have.

Creating an Object

To create an object of a class, you use the new keyword followed by the class name and any required arguments for the constructor

Difference between object and class

Class	Object
Class is the blueprint of an object. It is used to declare and create objects.	Object is an instance of class.
No memory is allocated when a class is declared.	Memory is allocated as soon as an object is created.
A class is a group of similar objects.	Object is a real-world entity such as book, car, etc.
Class is a logical entity.	Object is a physical entity.
Class can only be declared once.	Object can be created many times as per requirement.
Example of class can be car.	Objects of the class car can be BMW, Mercedes, jaguar, etc.

1. Conditional Statements

if-else

• Used to execute code based on conditions.
• Provides alternative paths based on different conditions.
• Example:
• if (condition) { … } else if (anotherCondition) { … } else { … }

switch

• Provides a way to execute different actions based on the value of a variable.
• Offers a cleaner alternative to nested if-else statements for multiple conditions.
• Example:
• switch (variable) { case value1: … break; case value2: … break; default: … break; }

2. Loops

for Loop

• Iterates a statement or a block of statements repeatedly until a specified condition is met.
• Typically used when the number of iterations is known.
• Example:
• for (int i = 0; i < 5; i++) { … }

while Loop

• Repeats a statement or a block of statements while a given condition is true.
• Example:
• while (condition) { … }

do-while Loop

• Executes a block of statements repeatedly until a specified condition becomes false.
• Example:
• do { … } while (condition);

foreach Loop

• Iterates over a collection of items such as arrays or collections.
• Simplifies iteration without explicitly initializing a counter variable.
• Example:
• foreach (type variable in collection) { … }

C# Operators types

1. Arithmetic Operators

• Addition (+)
  • Adds two operands
  • Example: int sum = a + b;
• Subtraction (-)
  • Subtracts second operand from the first
  • Example: int difference = a – b;
• Multiplication (*)
  • Multiplies two operands
  • Example: int product = a * b;
• Division (/)
  • Divides numerator by denominator
  • Example: int quotient = a / b;
• Modulus (%)
  • Returns remainder of division
  • Example: int remainder = a % b;

2. Comparison Operators

Equal to (==)

• Checks if two operands are equal
• Example: bool isEqual = a == b;

Not equal to (!=)

• Checks if two operands are not equal
• Example: bool isNotEqual = a != b;

Greater than (>)

• Checks if the left operand is greater than  the right
• Example: bool isGreater = a > b;

Less than (<)

• Checks if the left operand is less than the right
• Example: bool isLess = a < b;

Greater than or equal to (>=)

• Checks if the left operand is greater than or equal to the right
• Example: bool isGreaterOrEqual = a >= b;

Less than or equal to (<=)

• Checks if the left operand is less than or equal to the right
• Example: bool isLessOrEqual = a <= b;

3. Logical Operators

Logical AND (&&)

• Returns true if both operands are true
• Example: bool result = a && b;

Logical OR (||)

• Returns true if either operand is true
• Example: bool result = a || b;

Logical NOT (!)

• Reverses the logical state of its operand
• Example: bool result = !a;

4. Assignment Operators

Assignment (=)

• Assigns right operand to left operand
• Example: a = b;

Addition assignment (+=)

• Adds right operand to left operand and assigns the result to the left operand
• Example: a += b;

Subtraction assignment (-=)

• Subtracts right operand from left operand and assigns the result to the left operand
• Example: a -= b;

Multiplication assignment (*=)

• Multiplies left operand by right operand and assigns the result to the left operand
• Example: a *= b;

Division assignment (/=)

• Divides left operand by right operand and assigns the result to the left operand
• Example: a /= b;

Modulus assignment (%=)

• Calculates modulus using two operands and assigns the result to the left operand
• Example: a %= b;

5. Increment and Decrement Operators

• Increment (++)

• Increases an integer value by one
• Example: a++;

• Decrement (–)

• Decreases an integer value by one
• Example: a–;

6. Conditional Operator (Ternary Operator)

• Conditional (?:)

• Evaluates a boolean expression and returns the result of one of two expressions
• Example: string result = (a == b) ? “Equal” : “Not Equal”;