Putting it together

C# course · Intermediate · Lesson 23/116

Combine helper methods into a single class.

Putting it together

You have reached the end of five lessons. The Helpers static class now has three helper methods: Capitalize, Clamp and FormatDate. In this final lesson you will call all of them together.

The power of a helper library comes from methods being used together. For example, you can fix a user-entered name with Capitalize, squeeze their age into 0-120 with Clamp, and print their registration date in standard form with FormatDate. All from one class.

Using helpers together

Calling the three methods together shows how Helpers works as a toolkit. Each handles a separate task; together they form a user-record cleanup flow.

Extending this later is easy: to add a new helper, you just write a method in the class. The callers do not change, the class name does not change. That is the mark of a well-designed library: simple to extend, easy to use.

Exercise Call all three helpers together

The Helpers class below has all three helpers ready. Inside Main call all three and print their results: Helpers.Capitalize("hello"), Helpers.Clamp(15, 0, 10) and Helpers.FormatDate(new DateTime(2024, 3, 15)).

Show example solution

Capitalize, Clamp and FormatDate.
Example solution:
using System;

static class Helpers
{
    public static string Capitalize(string text)
    {
        if (string.IsNullOrEmpty(text)) return text;
        return char.ToUpper(text[0]) + text.Substring(1);
    }

    public static int Clamp(int value, int min, int max)
    {
        if (value < min) return min;
        if (value > max) return max;
        return value;
    }

    public static string FormatDate(DateTime date)
    {
        return date.ToString("yyyy-MM-dd");
    }
}

class Program
{
    static void Main()
    {
        Console.WriteLine(Helpers.Capitalize("hello"));
        Console.WriteLine(Helpers.Clamp(15, 0, 10));
        Console.WriteLine(Helpers.FormatDate(new DateTime(2024, 3, 15)));
    }
}

Library complete

Your helper library is ready. The Helpers static class has three methods: Capitalize fixes text, Clamp keeps numbers in range, FormatDate formats dates. You can copy it into any project and use it.

The next group covers encapsulation: the public, private, protected and internal access modifiers, get/set properties, and how to protect your class's interior with init and required members.

Test yourself

Why is a helper library written as a static class?
- It compiles faster
- It is called without an instance, reducing repetition
- It uses less memory
- It allows inheritance
Show answer

It is called without an instance, reducing repetition — Correct. A static class needs no instance; methods are called directly.
Match each helper to its purpose

Capitalize

Text formatting
Clamp

Number range
FormatDate

Date format
Helpers

Static library

Complete the helper call

Console.WriteLine(Helpers.____("hello"));

Show answer

Console.WriteLine(Helpers.Capitalize("hello"));

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Putting it together