what's the purpose of typename assignment inside templates

Question

I have come across this piece of code (I\'m trying to include all details in case I\'m missing something):

template< typename TYPE = TYPE_with_an_arbitrar         


        

Answer 1

These are default template arguments. You can use template default arguments to simplify their usage.

When you have two template parameters, for example, and give the last one a default type, you must specify only one type.

std::vector, for example, is defined as

template < class T, class Allocator = allocator > class vector;

Here you have a default template argument for Allocator, so you can define vectors with just one argument

std::vector v;