Record structs in C Sharp (C#) - Step-by-Step Execution

Concept Flow - Record structs

Define record struct

↓

Create instance with values

↓

Use instance: access properties

↓

Compare instances (value equality)

↓

Immutable by default, can use with-expressions

↓

End

This flow shows how a record struct is defined, instantiated, used, compared, and how its immutability works.

Execution Sample

C Sharp (C#)

public record struct Point(int X, int Y);

var p1 = new Point(3, 4);
var p2 = new Point(3, 4);

Console.WriteLine(p1 == p2);

Defines a record struct Point, creates two instances with same values, and compares them for equality.

Execution Table

Step	Action	Evaluation	Result
1	Define record struct Point with properties X and Y	N/A	Point type created
2	Create p1 = new Point(3, 4)	X=3, Y=4	p1 holds (3,4)
3	Create p2 = new Point(3, 4)	X=3, Y=4	p2 holds (3,4)
4	Compare p1 == p2	Compare values of X and Y	True
5	Print result	Output boolean	True

💡 Comparison done, program ends after printing True

Variable Tracker

Variable	Start	After Step 2	After Step 3	Final
p1	undefined	(3,4)	(3,4)	(3,4)
p2	undefined	undefined	(3,4)	(3,4)

Key Moments - 3 Insights

Why does p1 == p2 return True even though they are different instances?

Record structs compare their contents (values) for equality, not their memory addresses. See execution_table step 4 where values (3,4) are compared.

Are record structs mutable like classes?

No, record structs are immutable by default, meaning their properties cannot be changed after creation unless explicitly declared mutable.

What happens if we try to change a property of p1 after creation?

Since properties are readonly by default, the compiler will give an error. You must create a new instance with desired changes.

Visual Quiz - 3 Questions

Look at the execution_table at step 4, what is the result of comparing p1 and p2?

A False

B True

C Compilation error

D Runtime exception

💡 Hint

Check the 'Result' column in execution_table row 4.

According to variable_tracker, what is the value of p2 after step 3?

A (0,0)

B undefined

C (3,4)

D null

💡 Hint

Look at variable_tracker row for p2 under 'After Step 3'.

If we try to assign p1.X = 5 after creation, what will happen?

A Compilation error due to immutability

B Runtime exception

C The value of p1.X changes to 5

D p1 becomes null

💡 Hint

Refer to key_moments about immutability and property changes.

Concept Snapshot

Record structs are value types with immutable properties by default.
They support value-based equality (== compares contents).
Defined with 'record struct' syntax.
Instances are created with positional parameters.
Properties cannot be changed after creation unless mutable.
Use with-expressions to create modified copies.

Full Transcript

This example shows how to define a record struct named Point with two properties X and Y. We create two instances p1 and p2 with the same values (3,4). When we compare p1 and p2 using ==, the result is True because record structs compare their values, not references. The variables p1 and p2 hold the values (3,4) after creation. Record structs are immutable by default, so trying to change a property after creation causes a compilation error. This behavior ensures safe and predictable value semantics.