lst-0253-book.cpp
// https://godbolt.org/z/Exh4PnMTE
#include <string>
#include <string_view>
using std::string; using sview = std::string_view;
struct Person {
string name_;
int alter_;
string ort_;
Person(sview n = "N.N.", int a = 18, sview o = "Berlin")
: name_(n), alter_(a), ort_(o) { }
};