When and Why Are Static Variables Useful in C#?

Understanding Static Variables in C#

Static variables in C# are a powerful tool, but their usage is specific. Crucially, a static variable maintains its value across all instances of a class. This contrasts with non-static variables:

<code class="language-csharp">public class Variable
{
    public int i = 5;
    public void test()
    {
        i = i + 5;
        Console.WriteLine(i);
    }
}</code>

Here, each instance of Variable has its own independent i value. However, with a static variable:

<code class="language-csharp">public class Variable
{
    public static int i = 5;
    public void test()
    {
        i = i + 5;
        Console.WriteLine(i);
    }
}</code>

All instances share the same i value. Changing i in one instance affects all others.

The restriction against declaring static variables within methods is intentional. Static variables belong to the class itself, not a specific method call. Their role is to persist across instances and the program's execution. Therefore, declaring them within methods is logically inconsistent and disallowed.

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