Lambda expression syntax in C Sharp (C#) - Step-by-Step Execution

Concept Flow - Lambda expression syntax

Start

↓

Define parameters

→Use => operator

↓

Lambda created

↓

Use lambda

↓

End

This flow shows how a lambda expression is created by defining parameters, using the => operator, and writing an expression or block, resulting in a lambda that can be used.

Execution Sample

C Sharp (C#)

Func<int, int> square = x => x * x;
int result = square(4);
Console.WriteLine(result);

Defines a lambda that squares a number, calls it with 4, and prints the result.

Execution Table

Step	Action	Evaluation	Result
1	Define lambda: x => x * x	Create function that returns x squared	Lambda assigned to 'square'
2	Call square(4)	Calculate 4 * 4	16
3	Print result	Output 16	Console shows: 16
4	End	No more code	Execution stops

💡 Execution stops after printing the result.

Variable Tracker

Variable	Start	After Step 1	After Step 2	Final
square	null	lambda function (x => x * x)	lambda function	lambda function
result	undefined	undefined	16	16

Key Moments - 3 Insights

Why do we use the => symbol in lambda expressions?

The => symbol separates the input parameters from the expression or block that defines the lambda's behavior, as shown in step 1 of the execution_table.

What happens when we call the lambda with an argument?

The lambda runs the expression using the argument value, like in step 2 where 4 is squared to get 16.

Is the lambda executed when it is defined or when it is called?

The lambda is created when defined (step 1) but only runs when called (step 2), as the execution_table shows.

Visual Quiz - 3 Questions

Look at the execution_table, what is the value of 'result' after step 2?

A null

B 4

C 16

D undefined

💡 Hint

Check the 'result' variable in variable_tracker after step 2.

At which step is the lambda function assigned to the variable 'square'?

A Step 1

B Step 3

C Step 2

D Step 4

💡 Hint

Look at the action in execution_table step 1.

If we change the lambda to x => x + 1, what would be the output at step 3?

A 16

B 5

C 4

D 1

💡 Hint

The lambda adds 1 to the input; input is 4, so output is 5.

Concept Snapshot

Lambda expression syntax in C#:
(parameters) => expression_or_block
Creates an anonymous function.
Used to write short functions inline.
Called like normal functions.
=> separates parameters and body.

Full Transcript

This visual execution shows how a lambda expression is created and used in C#. First, a lambda is defined with parameters and an expression separated by the => operator. Then, the lambda is called with an argument, which runs the expression and returns a result. Finally, the result is printed. Variables 'square' and 'result' change as the code runs. Key points include understanding the => symbol, when the lambda runs, and how the result is produced.