Can Someone Explain This Snippet (Why Are These Braces Here)?

Question

I apologize for this overly simplistic question, but I can't seem to figure out this example in the book I'm reading:

void f5()
{
    int x;
    {
        int y;
    }
}

What are the braces surrounding int y for? Can you put braces wherever you want? If so, when and why would you do so or is this just an error in the book?

Answer 1

Braces like that indicate that the code inside the braces is now in a different scope. If you tried to access y outside of the braces, you would receive an error.

Answer 2

It's a matter of scoping variables, e.g.:

void f5()
{
    int x = 1;
    {
        int y = 3;
        y = y + x;          // works
        x = x + y;          // works
    }
    y = y + x;              // fails
    x = x + y;              // fails
}

Answer 3

It's defining scope. The variable Y is not accessible outside the braces.

Answer 4

The braces denote scope, the variable x will be visible in the scope of the inner brace but y will not be visible outside of it's brace scope.