Understanding the If-Else Statement in C# (Full Explanation with Examples)

Introduction: What is an If-Else Statement in C#?

In C#, the if-else statement is a fundamental decision-making structure used to execute blocks of code based on certain conditions.
It allows your program to make decisions and control its flow depending on whether a condition evaluates to true or false.

This blog will guide you through the different types of if-else statements in C#, along with explanations and practical examples.

1. Simple If Statement

The simplest form of the if statement evaluates a condition. If the condition evaluates to true, the associated block of code is executed.

Syntax:

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

Example:

int num = 10;
if (num > 0)
{
    Console.WriteLine("The number is positive.");
}

Explanation:
In this example, the condition num > 0 evaluates to true, so the message "The number is positive." is printed.

2. If-Else Statement

The if-else statement adds an else block, which is executed when the condition of the if statement evaluates to false.

Syntax:

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

Example:

int num = -5;
if (num > 0)
{
    Console.WriteLine("The number is positive.");
}
else
{
    Console.WriteLine("The number is non-positive.");
}

Explanation:
In this case, num > 0 evaluates to false, so the "The number is non-positive." message is printed.

3. If-Else If Ladder

The if-else if ladder chains multiple conditions, allowing you to evaluate several conditions in sequence. Each condition is checked, and the block of code for the first true condition is executed. If none of the conditions are true, the else block (if provided) is executed.

Syntax:

if (condition1)
{
    // Code to execute if condition1 is true
}
else if (condition2)
{
    // Code to execute if condition2 is true
}
else
{
    // Code to execute if none of the conditions are true
}

Example:

int num = 10;
if (num < 0)
{
    Console.WriteLine("The number is negative.");
}
else if (num > 0)
{
    Console.WriteLine("The number is positive.");
}
else
{
    Console.WriteLine("The number is zero.");
}

Explanation:
Since num > 0 evaluates to true, the message "The number is positive." is printed.

4. Nested If-Else Statements

Nested if-else statements involve placing an if or else statement inside another if or else block. This allows for more complex decision-making.

Syntax:

if (condition1)
{
    if (condition2)
    {
        // Code to execute if both conditions are true
    }
    else
    {
        // Code to execute if condition1 is true but condition2 is false
    }
}
else
{
    // Code to execute if condition1 is false
}

Example:

int num = 10;
if (num >= 0)
{
    if (num == 0)
    {
        Console.WriteLine("The number is zero.");
    }
    else
    {
        Console.WriteLine("The number is positive.");
    }
}
else
{
    Console.WriteLine("The number is negative.");
}

Explanation:
Since num >= 0 is true, the inner if statement checks if num == 0. Since it's false, "The number is positive." is printed.

Conclusion: Using If-Else Statements in C#

The if-else statement is one of the core control flow tools in C#, allowing you to control the execution of code based on dynamic conditions.
Whether you're making simple decisions with a basic if statement or chaining multiple conditions with else-if ladders or nesting them for complex logic, if-else helps create flexible, dynamic behavior in your applications.

Mastering if-else will improve your decision-making logic and ensure that your programs can respond to various conditions dynamically.

Understanding the If-Else Statement in C# (Full Explanation with Examples)