Why reference const can be re-assigned in for-statement?

Question

I\'m new to C++, and I\'m confused about this:

vector v = { 1,2 };
const int &r1 = v[0];
//r1 = v[1];  // compiler will show error.
         


        

Answer 1

The ranged-based for looks like this:

attr(optional) for ( range_declaration : range_expression ) loop_statement

where range_declaration is

range_declaration - a declaration of a named variable, whose type is the type of the element of the sequence represented by range_expression, or a reference to that type. Often uses the auto specifier for automatic type deduction

So each iteration a new declaration is introduced, the reference only exists until the next loop iteration.