Explain the Conditional Statements in C#. if, if-else, else-if.

Introduction

In C#, conditional statements allow you to make decisions based on specific conditions. The most common conditional statements are if, if-else, and else if. Let’s break down each type with syntax, explanations, and examples.

1. if Statement

The if statement evaluates a condition. If the condition is true, it executes a block of code; if it’s false, it skips the code block.

Syntax:

if (condition)
{
    // Code to execute if condition is true
}

Example

int age = 20;

if (age >= 18)
{
    Console.WriteLine("You are eligible to vote.");
}

In this example, if age is greater than or equal to 18, it will print “You are eligible to vote.” If age is less than 18, nothing happens, as there is no alternate path specified.

2. if-else Statment

The if-else statement provides an alternative block of code to execute if the condition in the if statement is false.

Syntax

if (condition)
{
    // Code to execute if condition is true
}
else
{
    // Code to execute if condition is false
}

Example

int age = 15;

if (age >= 18)
{
    Console.WriteLine("You are eligible to vote.");
}
else
{
    Console.WriteLine("You are not eligible to vote.");
}

In this example, if age is less than 18, the program prints “You are not eligible to vote.” Here, the else block provides a fallback for when the if condition is false.

3. else-if Statment

he else if statement allows you to check multiple conditions. After an if statement, you can use one or more else if statements to test additional conditions. If any condition evaluates to true, its corresponding code block executes, and the rest are skipped. If none of the if or else if conditions are true, you can add an optional else block to provide a final fallback.

Syntax

if (condition1)
{
    // Code to execute if condition1 is true
}
else if (condition2)
{
    // Code to execute if condition1 is false and condition2 is true
}
else if (condition3)
{
    // Code to execute if condition1 and condition2 are false and condition3 is true
}
else
{
    // Code to execute if all previous conditions are false
}

Example

int marks = 85;

if (marks >= 90)
{
    Console.WriteLine("Grade: A");
}
else if (marks >= 80)
{
    Console.WriteLine("Grade: B");
}
else if (marks >= 70)
{
    Console.WriteLine("Grade: C");
}
else
{
    Console.WriteLine("Grade: F");
}

In this example:

• If marks is 90 or higher, it will print “Grade: A”.
• If marks is between 80 and 89, it will print “Grade: B”.
• If marks is between 70 and 79, it will print “Grade: C”.
• If none of the above conditions are met (meaning marks is below 70), it will print “Grade: F”.