Is declaration of variables expensive?

Question

While coding in C, I came across the below situation.

int function ()
{
  if (!somecondition) return false;

  internalStructure  *str1;
  internalStructure *str         


        

Answer 1

Keep the declaration as close to where it's used as possible. Ideally inside nested blocks. So in this case it would make no sense to declare the variables above the if statement.