Func delegate type in C Sharp (C#) - Step-by-Step Execution

Concept Flow - Func delegate type

Define Func delegate

↓

Assign lambda or method

↓

Invoke Func delegate

↓

Execute method body

↓

Return result

↓

Use returned value

This flow shows how a Func delegate is defined, assigned a method or lambda, invoked, and returns a value used later.

Execution Sample

C Sharp (C#)

Func<int, int, int> add = (x, y) => x + y;
int result = add(3, 4);
Console.WriteLine(result);

This code defines a Func delegate that adds two integers, calls it with 3 and 4, and prints the result.

Execution Table

Step	Action	Evaluation	Result
1	Define Func delegate 'add' with lambda (x, y) => x + y	N/A	add is assigned a function that adds two ints
2	Invoke 'add' with arguments (3, 4)	Calls lambda with x=3, y=4	Executes 3 + 4
3	Calculate 3 + 4	7	Returns 7
4	Assign returned value to 'result'	result = 7	result holds 7
5	Print 'result'	Console.WriteLine(7)	Output: 7

💡 Execution stops after printing the result 7.

Variable Tracker

Variable	Start	After Step 2	After Step 4	Final
add	undefined	Func delegate assigned	Func delegate assigned	Func delegate assigned
result	undefined	undefined	7	7

Key Moments - 3 Insights

Why do we assign a lambda expression to the Func delegate?

The lambda defines the method body that the Func delegate will call. See execution_table step 1 where 'add' is assigned the lambda.

What happens when we invoke the Func delegate with arguments?

The delegate calls the lambda with those arguments, executing its code. See execution_table step 2 and 3 for the call and calculation.

How do we get the result from the Func delegate?

The delegate returns the value from the lambda, which we store in 'result'. See execution_table step 4.

Visual Quiz - 3 Questions

Look at the execution_table, what is the value of 'result' after step 4?

A 3

B undefined

C 7

D 4

💡 Hint

Check the 'result' variable in variable_tracker after step 4.

At which step does the Func delegate actually perform the addition?

A Step 1

B Step 3

C Step 2

D Step 5

💡 Hint

Look at execution_table where the calculation 3 + 4 happens.

If we changed the lambda to (x, y) => x * y, what would be the output at step 5?

A 12

B 3

C 7

D 4

💡 Hint

Multiplying 3 and 4 gives 12, check how the lambda affects the result.

Concept Snapshot

Func delegate type syntax:
Func<T1, T2, TResult> delegateName = (param1, param2) => expression;
It holds a method that takes inputs and returns a value.
Invoke it like a method: delegateName(args);
Returns the result of the method or lambda.
Useful for passing methods as variables.

Full Transcript

This example shows how to use the Func delegate type in C#. First, we define a Func delegate named 'add' that takes two integers and returns their sum using a lambda expression. Then, we call 'add' with the numbers 3 and 4. The delegate executes the lambda, adds the numbers, and returns 7. We store this result in the variable 'result' and print it. The output is 7. This demonstrates how Func delegates hold methods or lambdas that return values and how to invoke them.