lst-0034-book.cpp
// https://godbolt.org/z/jGx51caTj
#include <vector>
#include <iostream>
void printAndMore(const std::vector<int>& data) { // by-const-ref
std::cout << data[0] << std::endl;
data[0] = 666; // (ERR) doesn't work because 'const int&'
}
int main() {
std::vector numbers {1,2,3};
printAndMore(numbers);
}