#include <algorithm>
#include <cctype>
#include <iomanip>
#include <iostream>
#include <string>
#include <vector>
 
void print_ordinals(std::vector<std::size_t> const& ordinals)
{
    std::cout << "ordinals: ";
    for (std::size_t ord : ordinals)
        std::cout << std::setw(3) << ord << ' ';
    std::cout << '\n';
}
 
int main()
{
    std::string s{"hello"};
    std::transform(s.cbegin(), s.cend(),
                   s.begin(), // write to the same location
                   [](unsigned char c) { return std::toupper(c); });
    std::cout << "s = " << std::quoted(s) << '\n';
 
    // achieving the same with std::for_each (see Notes above)
    std::string g{"hello"};
    std::for_each(g.begin(), g.end(), [](char& c) // modify in-place
    {
        c = std::toupper(static_cast<unsigned char>(c));
    });
    std::cout << "g = " << std::quoted(g) << '\n';
 
    std::vector<std::size_t> ordinals;
    std::transform(s.cbegin(), s.cend(), std::back_inserter(ordinals),
                   [](unsigned char c) { return c; });
 
    print_ordinals(ordinals);
 
    std::transform(ordinals.cbegin(), ordinals.cend(), ordinals.cbegin(),
                   ordinals.begin(), std::plus<>{});
 
    print_ordinals(ordinals);
}