0.3.15 Reading a Simple if Statement

An if Statement Lets One Action Depend on a Condition

You have already seen Boolean values such as:

Activity diagram showing Evaluate condition, then Run the if block, then Continue after the if. — EvaluateCondition.

When the condition is false

Activity diagram showing Evaluate condition, then Skip the if block, then Continue after the if. — EvaluateCondition.

Both paths eventually continue after the if.

Connect the Code to an Activity Diagram

The C#:

if (player1.isAvailable)
{
    System.Console.WriteLine("Player is available.");
}

can be connected to a simple activity-diagram idea:

Activity diagram showing Decision: Is the player available?, then [yes] Display "Player is available.", then [no] Continue. — DecisionIsThePlayerAvailable.

The notation is different, but the reasoning is the same:

Evaluate a condition → follow the path that applies

The activity diagram makes the flow visual.

The C# makes the behavior executable.

The Condition Does Not Need == true

Because player1.isAvailable is already Boolean, this is enough:

if (player1.isAvailable)
{
    System.Console.WriteLine("Player is available.");
}

You may sometimes encounter code written as:

if (player1.isAvailable == true)
{
    System.Console.WriteLine("Player is available.");
}

For a Boolean value, the extra comparison is not needed to express the idea.

At this stage, the shorter form keeps the condition easier to read.

Indentation Helps Humans See the Structure

Compare:

if (player1.isAvailable)
{
    System.Console.WriteLine("Player is available.");
}

with poorly arranged code:

if (player1.isAvailable)
{
System.Console.WriteLine("Player is available.");
}

The compiler uses C# syntax to determine structure, but consistent indentation makes the controlled statements easier for people to recognize.

When reading unfamiliar code, use both the braces and the indentation to understand which statements belong to the if.

Use the Debugger to Observe the Path

A breakpoint placed before the if lets you inspect the Boolean value before the decision occurs.

Suppose the debugger shows:

player1.isAvailable = true

You can predict that the block should run.

Using F10 lets you step through the decision and see which statement Visual Studio selects next.

If the debugger instead shows:

player1.isAvailable = false

the program should skip the block and continue after the if.

This connects three forms of evidence:

the Boolean state;
the C# decision;
the path you observe at runtime.

Keep the Meaning Simple

A basic if statement answers one question:

If the condition is true, yes.

If the condition is false, no.

Later programming work will use more complicated conditions and several connected decision structures. For now, focus on reading one Boolean condition and tracing the one block it controls.