C# by Example: Functions


public class FunctionExample {

Functions are named blocks of re-usable code. If a function belongs to a class, like these do, we call it a 'Method'.

Functions are defined much like variables: a return type then a name. After the name, we use parentheses. The parentheses are how C# know's it's a function. Inside them, we put parameters, variables used by the function.


    public string Emphasize(string parameter)
    {
        return parameter+"!";
    }

If we don't define a scope, they are private by default. If we don't return a value, we have to use the "void" placeholder as the functions return type.


    void Banana()
    {

Calling a function is as simple as typing it's name - don't forget the parentheses and arguments (data to pass into the function) that matches the functions parameters (input variables).


        string ouput = Emphasize("Bananas");
        Console.WriteLine(ouput);
    }

Functions can have any number of arguments.


    public int SumFourThings(int a, int b,int c, int d)
    {
        return a+b;
    }
    public void Test()
    {

When calling a function, we pass the data in using the order of the parameters. The names of parameters don't matter, but are important for readability.


        int sum = SumFourThings(1,2,3,4);

You can define functions inside of other functions. This isn't very common. It's a bit of a red flag: is there another way to structure your code? Maybe a static Utilities class.


        string SayHello()
        {
            return "Hello";
        }
        Console.WriteLine(SayHello());
    }
}

Further:

Next example: Loops.