9.5.2

9.43

void replace_with(string &s, string const& oldVal, string const& newVal)
{
    for (auto cur = s.begin(); cur <= s.end() - oldVal.size(); )
        if (oldVal == string{ cur, cur + oldVal.size() })
            cur = s.erase(cur, cur + oldVal.size()),
            cur = s.insert(cur, newVal.begin(), newVal.end()),
            cur += newVal.size();
        else  
            ++cur;
}

9.44

void replace_with(string &s, string const& oldVal, string const& newVal)
{
    for (size_t pos = 0; pos <= s.size() - oldVal.size();)
        if (s[pos] == oldVal[0] && s.substr(pos, oldVal.size()) == oldVal)
            s.replace(pos, oldVal.size(), newVal),
            pos += newVal.size();
        else
            ++pos;
}

9.45

auto add_pre_and_suffix(string name, string const& pre, string const& su)
{
    name.insert(name.begin(), pre.cbegin(), pre.cend());
    return name.append(su);
}

9.46

auto add_pre_and_suffix(std::string name, std::string const& pre, std::string const& su)
{
    name.insert(0, pre);
    name.insert(name.size(), su);
    return name;
}