Expression-bodied methods in C Sharp (C#) - Step-by-Step Execution

Concept Flow - Expression-bodied methods

Method Declaration

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Use => expression

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Evaluate expression

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Return result

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Method call outputs value

An expression-bodied method uses => followed by an expression to return a value directly, making the method concise.

Execution Sample

C Sharp (C#)

int Square(int x) => x * x;

int result = Square(3);
Console.WriteLine(result);

Defines a method that returns the square of a number using expression-bodied syntax and prints the result.

Execution Table

Step	Action	Expression Evaluated	Result	Output
1	Call Square(3)	3 * 3	9
2	Return from Square	9	9
3	Assign to result		result = 9
4	Print result			9

💡 Method call completes and program prints 9, then ends.

Variable Tracker

Variable	Start	After Call	Final
x	-	3	3
result	-	-	9

Key Moments - 2 Insights

Why is there no curly braces {} in the method?

Expression-bodied methods use => to directly return the expression result, so curly braces and return keyword are not needed (see execution_table step 1).

What happens if the expression is more complex?

The expression after => can be any single expression; it will be evaluated and returned directly, keeping the method concise.

Visual Quiz - 3 Questions

Look at the execution_table at step 1, what is the value of the expression evaluated?

A 3

B 6

C 9

D 0

💡 Hint

Check the 'Expression Evaluated' column at step 1 in the execution_table.

At which step is the method's return value assigned to the variable 'result'?

A Step 3

B Step 1

C Step 2

D Step 4

💡 Hint

Look at the 'Action' column in execution_table for assignment to 'result'.

If the method was written with curly braces and a return statement, how would the execution_table change?

A The output would change

B Steps would include 'Enter method' and 'Return value' explicitly

C The expression evaluated would be different

D No change at all

💡 Hint

Think about how expression-bodied methods simplify the method body compared to traditional syntax.

Concept Snapshot

Expression-bodied methods use => followed by an expression to return a value directly.
They replace curly braces and return statements for simple methods.
Syntax: ReturnType MethodName(params) => expression;
Useful for concise, single-expression methods.
Called like normal methods and return the expression result.

Full Transcript

This example shows how expression-bodied methods work in C#. The method Square takes an integer x and returns x multiplied by itself using the => syntax. When Square(3) is called, the expression 3 * 3 is evaluated to 9, which is returned and assigned to the variable result. Finally, result is printed as 9. Expression-bodied methods let us write short methods without curly braces or return statements, making code cleaner and easier to read.