Question

When I write something like this:

int data[] = {10,44,56,78,8};      
int i = 0;
for(int element : data)
   ...

that for is then translated by the compiler in a regular for? is that for
only a syntactic sugar?

Answer 1

The standard defines the range-based for statement to be equivalent to:

{
  auto && __range = range-init;
  for ( auto __begin = begin-expr,
             __end = end-expr;
        __begin != __end;
        ++__begin ) {
    for-range-declaration = *__begin;
    statement
  }
}

In your case, range-init is (data), begin-expr is __range, end-expr is __range + 5, for-range-declaration is int element and statement is .... That is, if we substitute all of these, your for loop is equivalent to:

{
  auto && __range = (data);
  for ( auto __begin = __range,
             __end = __range + 5;
        __begin != __end;
        ++__begin ) {
    int element = *__begin;
    ...
  }
}

Whether this translation is actually done by the compiler is an implementation detail. The only thing you can guarantee is that your code will be equivalent to the above code.