#1,102 – Scope vs. Declaration Space

The terms scope and declaration space are similar, but slightly different.

  • Scope is the region of code in which you can refer to a named entity using its unqualified name.
  • Declaration space is a region of code within which you can’t declare two entities having the same name

For example:

    public class MyClass
    {
        int count1 = 1;
        int count2 = 2;

        public void AMethod()
        {
            int count2 = 22;

            Console.WriteLine(count1 + ", " + count2);
        }
    }

Then:

  • The class-level declarations of count1 and count2 are in the same scope and in the same declaration space
  • The body of function AMethod()
    • is included in the scope in which class-level fields are defined, i.e. you can reference them using their unqualified name.
    • defines a new declaration space, i.e. we can define a new variable of the same name as the class-level fields
    • defines a new scope, in which we can define variables, nested within outer scope

1102-001

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