Functions in C# with Examples - Dot Net Tutorials

Functions in C#

• Groups of related instructions that perform specific tasks, allowing code reusability and simplifying coding tasks.

• Take input as parameters and return a result as a return value.

Importance of Functions

• Break complex programs into manageable pieces.

• Each function handles specific tasks, enhancing code readability and maintainability.

• Organizes code and prevents redundancy.

Monolithic Programming

• Definition: All code resides in a single main function.

• Problems:

  • Errors in one line can disrupt the entire program.

  • Larger codebases become cumbersome to manage and understand.

  • Limits collaboration as only one person can work on the single main function.

  • Large programs may exceed memory limits.

Modular Programming

• Definition: Programs broken into smaller, reusable functions.

• Benefits:

  • Facilitates piece-wise development.

  • Encourages teamwork as different programmers can work on separate functions.

  • Increases code productivity and reusability.

Types of Functions in C#

• Built-in Functions:

  • Pre-defined functions in the C# framework.

  • Optimized for performance and saves development time.

• User-Defined Functions:

  • Defined by developers for specific tasks; allows customization and reduces program complexity.

Limitations of Built-in Functions

• Limited tasks; may necessitate user-defined functions for specific needs.

Creating User-Defined Functions in C#

• Naming: Mandatory, follows variable naming rules.

• Parameter List: Optional, can take multiple parameters or none.

• Return Type: Mandatory, defines type of value returned. A 'void' return type indicates no return value.

• Access Specifier: Optional, outlines method accessibility (e.g., public, private).

• Modifier: Optional, controls access type (e.g., static, virtual).

Example of User-Defined Function

using System;  
namespace FunctionDemo {  
    class Program {  
        static void Main(string[] args) {  
            int x = 10;  
            int y = 15;  
            int sum = Add(x, y);  
            Console.WriteLine($"Sum is {sum}");  
            Console.ReadKey();  
        }  
        static int Add(int a, int b) {  
            return a + b;  
        }  
    }  
}  

• In this example, the Add function takes two integers, computes their sum, and returns it to the calling function.

Function Parameters

• Actual Parameters: Values passed to functions (e.g., x, y in the example).

• Formal Parameters: Variables in the function signature (e.g., a, b in Add function).

• Actual parameters are copied into formal parameters during the function call.

Memory Management in Functions

• Each method has its own activation area; variables inside a function can't access variables of outside functions.

• Effective memory handling enhances performance and organization.

Return Statement in C#

• Terminates function execution and returns control to the calling function.

• Can return a value to the calling function.

• Used when the function is ready to return a value.

How to Call a Method in C#?

• Invoking a method requests an action (e.g., setting a value, printing statements, performing calculations).

• Code contains the method name and any necessary data specified in the parameter list.

• Control transfers to the called method, which returns control under three conditions:

  1. When the return statement is executed.

  2. When it reaches the closing curly brace.

  3. When it throws an unhandled exception.