Lære Method Parameters

Sometimes we need to pass some data into the methods so it can process that data and give us some output. For example, we can create a method that calculates the sum of three numbers and outputs the result. Such a thing can be achieved using method parameters.

We can create a method with parameters using the following syntax:

main.cs


              1234
            
static void methodName(dataType parameter1, dataType parameter2, ...)
{
    // Code to be executed
}

Here is the usage of the parameters:

main.cs


              12345
            
static void sumOfThree(int a, int b, int c) 
{
    int sum = a + b + c;
    Console.WriteLine($"The sum is {sum}");
}

Note

It's also possible to write expressions directly in string formatting, therefore writing Console.WriteLine($"The sum is {a + b + c}") is also valid in the above case.

In the above code the terms a, b, and c represent the passed data. When we are calling such a method we pass the data along with it. The syntax for executing/calling such a method is the following:

main.cs


              1
            
methodName(argument1, argument2, ...);

For example:

main.cs


              1
            
sumOfThree(1, 2, 3);

Note

An argument is a value that you pass to a method when calling it, for example 1, 2, and 3 in the above example are arguments. On the other hand, a parameter is a variable declared in the method's definition to receive and work with those arguments. In the above case a, b, and c are the parameters.

Here is the full code for the above example:

main.cs


              1234567891011121314151617
            
using System;

namespace ConsoleApp
{
    internal class Program
    {
        static void sumOfThree(int a, int b, int c)
        {
            Console.WriteLine($"The sum is {a + b + c}");
        }

        static void Main(string[] args)
        {
            sumOfThree(1, 2, 3);
        }
    }
}

The following illustration explains the flow:

When calling a method, we must always provide the required amount of arguments, otherwise, the code might not compile:

main.cs


              12345678910111213141516171819
            
using System;

namespace ConsoleApp
{
    internal class Program
    {
        static void sumOfThree(int a, int b, int c) 
        {
            int sum = a + b + c;
            Console.WriteLine($"The sum is {sum}");
        }

        static void Main(string[] args)
        {
            //sumOfThree(1, 2); // Error
            sumOfThree(5, 6, 7); // Valid
        }
    }
}

Note

In the code above, line sumOfThree(1, 2) will throw an error, because there are only 2 arguments provided. Required 3.

Apart from that, the order of the arguments must also match the definition of the method:

main.cs


              123456789
            
static void exampleMethod(int a, string b, bool c) {
    Console.WriteLine(a);
    Console.WriteLine(b);
    Console.WriteLine(c);
}

exampleMethod("Hello", 1, true); // Invalid
exampleMethod(true, "Hello", 1); // Invalid
exampleMethod(1, "Hello", true); // Correct

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Sektion 6. Kapitel 4

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We can create a method with parameters using the following syntax:

main.cs


              1234
            
static void methodName(dataType parameter1, dataType parameter2, ...)
{
    // Code to be executed
}

Here is the usage of the parameters:

main.cs


              12345
            
static void sumOfThree(int a, int b, int c) 
{
    int sum = a + b + c;
    Console.WriteLine($"The sum is {sum}");
}

Note

It's also possible to write expressions directly in string formatting, therefore writing Console.WriteLine($"The sum is {a + b + c}") is also valid in the above case.

main.cs


              1
            
methodName(argument1, argument2, ...);

For example:

main.cs


              1
            
sumOfThree(1, 2, 3);

Note

An argument is a value that you pass to a method when calling it, for example 1, 2, and 3 in the above example are arguments. On the other hand, a parameter is a variable declared in the method's definition to receive and work with those arguments. In the above case a, b, and c are the parameters.

Here is the full code for the above example:

main.cs


              1234567891011121314151617
            
using System;

namespace ConsoleApp
{
    internal class Program
    {
        static void sumOfThree(int a, int b, int c)
        {
            Console.WriteLine($"The sum is {a + b + c}");
        }

        static void Main(string[] args)
        {
            sumOfThree(1, 2, 3);
        }
    }
}

The following illustration explains the flow:

When calling a method, we must always provide the required amount of arguments, otherwise, the code might not compile:

main.cs


              12345678910111213141516171819
            
using System;

namespace ConsoleApp
{
    internal class Program
    {
        static void sumOfThree(int a, int b, int c) 
        {
            int sum = a + b + c;
            Console.WriteLine($"The sum is {sum}");
        }

        static void Main(string[] args)
        {
            //sumOfThree(1, 2); // Error
            sumOfThree(5, 6, 7); // Valid
        }
    }
}

Note

In the code above, line sumOfThree(1, 2) will throw an error, because there are only 2 arguments provided. Required 3.

Apart from that, the order of the arguments must also match the definition of the method:

main.cs


              123456789
            
static void exampleMethod(int a, string b, bool c) {
    Console.WriteLine(a);
    Console.WriteLine(b);
    Console.WriteLine(c);
}

exampleMethod("Hello", 1, true); // Invalid
exampleMethod(true, "Hello", 1); // Invalid
exampleMethod(1, "Hello", true); // Correct

Var alt klart?

Tak for dine kommentarer!

Sektion 6. Kapitel 4