lst-0021-book.cpp
vector<Number*> primePointers(unsigned long upTo) { // (ERR) Vector of pointers is suspicious
vector<Number> allNumbers;
vector<Number*> primes{};
// …
for(Number &z : allNumbers)
if(isPrime(z, primes))
primes.push_back( &z ); // store address
return primes; // (ERR) Pointers to function-local objects
}