#include <chrono>#include <iostream> int main(){usingnamespace std::chrono_literals; std::chrono::hours z_hours{};std::chrono::seconds z_seconds{}; z_hours= 2h;// ok, no conversion needed z_seconds= z_hours;// First, the converting ctor is used to create a temporary object of `lhs`s type.// This ctor implicitly invokes the casting function// chrono::duration_cast<std::seconds>(z_hours). The resulting `rhs` rvalue// has the same type as `lhs`, and the `operator=` finally performs the assignment. std::cout<<"hours: "<< z_hours.count()<<'\n';std::cout<<"seconds: "<< z_seconds.count()<<'\n'; z_seconds-= 42s; // z_hours = z_seconds; // compile-time error (which is good): incompatible types.// The library avoids the implicit cast to prevent a potential precision loss. z_hours=std::chrono::duration_cast<std::chrono::hours>(z_seconds);// ok z_hours=std::chrono::duration_cast<decltype(z_hours)>(z_seconds);// ditto std::cout<<"hours: "<< z_hours.count()<<'\n';std::cout<<"seconds: "<< z_seconds.count()<<'\n'; std::chrono::duration<double,std::ratio<3600>> z2_hours{}; z2_hours= z_seconds;// ok, no truncation, implicit cast std::cout<<"hours: "<< z2_hours.count()<<'\n';}
