Namespaces and where classes live

A namespace is a surname for a group of classes. It lets two classes share a simple name without clashing.

Your classes and the framework classes

The framework ships thousands of classes, grouped into namespaces by purpose. Your classes live in a namespace you choose. A using statement at the top of a file saves you from typing the full name every time.

using System;
using System.Collections.Generic;

namespace MyPractice
{
    public class Lesson { }
}

Why it matters

• Two libraries can both define a class called Item without conflict.
• A clear namespace tells a reader what part of a system a class belongs to.
• Using statements keep your code short while staying unambiguous.

With names settled, add more detail to a class in a second class with more detail.