Modernes C++ programmieren

//#(compile) c++; compiler:g132; options:-O3 -std=c++23; libs:-
// https://godbolt.org/z/9vP3o68bW 
#include <iostream>
#include <string>
#include <concepts>    // copyable, C++20
template <std::copyable T>
class MyContainer {
    T data_;
public:
    void setData(const T& d) { data_ = d; }
    T getData() const { return data_; }
};

class IntValue {
    int val_;
public:
    explicit IntValue(int val=0) : val_(val) {}
    int getInt() const { return val_; }
};
int main() {
    // C-array with three MyContainer<double> instances
    MyContainer<double> dcont[3];
    dcont[0].setData(123.123);
    dcont[1].setData(234.234);
    std::cout << dcont[0].getData() << std::endl;
    std::cout << dcont[1].getData() << std::endl;
    // custom data type as formal parameter
    IntValue ival{100'000};
    MyContainer<IntValue> scont;
    scont.setData(ival);
    std::cout << scont.getData().getInt() << std::endl;
    // string as formal parameter
    std::string str("Text");
    MyContainer<std::string> strCont;
    strCont.setData(str);
    std::cout << strCont.getData() << std::endl;
}