Kursusindhold

C# Basics

1. Getting Started

Why C#?C# Syntax Displaying Output Challenge: Outputting a Triangle Comments Challenge: Comments Variables Identifiers Challenge: Variable Declaration Basic Operators & Expressions Challenge: Operators

2. Dealing with Data Types

Integer Data Types Challenge: Declaring Explicitly Typed Variables Floating-Point and Double Booleans Character String Strings Challenge Basic String Formatting Challenge: String Formatting Declaring Constants Basic Type Casting Type Casting Practice Basic Type Conversion Basic Coding Practice

3. Control Structures

Comparison Operators Logical Operators Challenge: Operators Order of Operations If Statement Challenge: if Condition else Keyword Challenge: else Keyword if-else Chain Challenge: if, else-if, else switch Statement Challenge: Switch

4. Loops

for Loop Challenge: for Loop while Loop do-while Loop Challenge: do-while Loop break Statement continue Statement Challenge: break and continue

5. Arrays

What are Arrays?Challenge: Array Declaration Indexing Challenge: Indexing Multi-Dimensional Arrays Challenge: Multi-Dimensional Arrays Looping through Arrays Challenge: Array Loops

6. Methods

What are Methods?Creating and Calling Methods Challenge: Methods Creation Method Parameters Challenge: Method with Parameters Method Return Values Challenge: Return Values Local & Global Scopes Challenge: Scopes What's Next?

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


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

Here is the usage of the parameters:

main


              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


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

For example:

main


              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


              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


              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


              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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Kursusindhold

C# Basics

1. Getting Started

2. Dealing with Data Types

3. Control Structures

4. Loops

for Loop Challenge: for Loop while Loop do-while Loop Challenge: do-while Loop break Statement continue Statement Challenge: break and continue

5. Arrays

What are Arrays?Challenge: Array Declaration Indexing Challenge: Indexing Multi-Dimensional Arrays Challenge: Multi-Dimensional Arrays Looping through Arrays Challenge: Array Loops

6. Methods

Method Parameters

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

main


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

Here is the usage of the parameters:

main


              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


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

For example:

main


              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


              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


              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


              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