Class template type deduction is a new feature added in C++17 that provides the ability to deduce the type of a template class from its constructor. Suppose we have the following class template:
template<typename T>class the_answer{public: the_answer(T t) { show_type(t); }};
As shown in the preceding code snippet, we have a simple class template that takes a type T during construction and uses a show_type() function to output whatever type it is given. Before C++17, this class would have been instantiated using the following:
int main(void){ the_answer<int> is(42);}
With C++17, we can now instantiate this class as follows:
int main(void){ the_answer is(42);}
The reason this works is that the constructor of the class takes ...
