lst-0662-book.cpp
// https://godbolt.org/z/jbafeEdoW
#include <iostream>
#include <concepts> // copyable, C++20
template<std::copyable T, std::copyable U=T>
class MyPair {
T data01_;
U data02_;
public:
MyPair(const T& t,const U& u) : data01_{t}, data02_{u} {}
void print(std::ostream& os) const {
os << data01_ << " : " << data02_ << std::endl;
}
};
int main() {
MyPair<double> zahlen{11.11, 22.22};
zahlen.print(std::cout);
}