Methods in C-Sharp

Methods

C# methods are, basically, a series of instructions inside a code block that *only run when it’s called. Methods, differently from functions, are always associated with an object. All instructions of a given method will be inside its code block, and declared within a class or struct.

For a method to be declared, it needs an access modifier and return type, and optionally can return or not a value, and pass or not parameters values:

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For example, let’s declare a method that returns the area of a given circle:

static float AreaOfCircle (float Radius)
{
    float pi = 3.1415f;
 
    return pi * (Radius * Radius);
}
 
Console.WriteLine(AreaOfCircle(5.5f)); // Returns 95.03f

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Method Overloading

For C# to call a method, it searches for a combination of a name, type, and number of parameters. Because of this, it’s possible for different methods to actually share the same name, if they differ in its parameters.

This characteristic is called Method Overloading, most commonly used to create different methods that do the same task, but with different parameters.

class MyMethods
{
	public decimal AreaOfCircle(int Radius)  // Uses int.
	{
		decimal pi = 3.1415m;
		return pi * (Radius * Radius);
	}
 
	public decimal AreaOfCircle(float Radius)  // Uses float.
	{
		decimal pi = 3.1415m;
		return pi * Convert.ToDecimal(Radius * Radius);
	}
		
}

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Optional Parameters and Named Arguments

It’s possible to create optional parameters, that will have default values in its declaration. It’s not needed to pass an argument to said parameter when calling the method, as it’ll use its default value.

To pass arguments that are not in order, it’s possible to use Named Arguments. This way, it doesn’t matter the order in which you pass the arguments, as long as all of them are passed.

static int CalculateAnnualWage(
int monthlyWage, int numberOfMonthsWorked,int annualBonus = 0
) 
	{
		return monthlyWage * numberOfMonthsWorked + annualBonus;
	}
 
int annualWage = CalculateAnnualWage(
	numberOfMonthsWorked: 12, monthlyWage:3500, annualBonus: 1000);
	// Note that the order is different from the declaration.
 
Console.WriteLine(annualWage); // Returns 43000

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Expression-bodied Methods

Using Expression-bodied Syntax to declare a method which will return a value from a simple task can be much more concise. Basically, we lose the curly brackets and replace the return statement by a fat arrow. Let’s take, for example, the method used to calculate the area of a circle.

static decimal AreaOfCircle(int Radius) => 3.1415m * (Radius * Radius);
// Still works the same as the one declared before.

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Parameters as Reference

It’s also possible to pass arguments as reference, instead of values. Check the ref and out keywords.

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Default Main Method

Every single code in C# comes wrapped inside the Program class and Main method. Even though, in newer versions of C# the compiler might do it implicitly, these are fundamental for specifying which file will be defined as Main and have top-level statements.

class Program
{
    static void Main(string[] args)
    {
        //program execution starts from here
    }
}

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• For more information about classes, structs and other custom data types, check this note!.