Why can't you declare a variable inside the expression portion of a do while loop?

Question

The following syntax is valid:

while (int i = get_data())
{
}

But the following is not:

do
{
} while (int i = get_data());
         


        

Answer 1

Add this

#define do(cond) switch (cond) do default:

at the beginning of your code.

Now, you can write

do (int i = get_data()) 
{

    // your code

} while ((i = get_data()));

It is important that this #define does not break the original syntax of the do keyword in do-while loop.

However, I admit that it is obscure.