std::string replace(const std::string& in, const std::string& from, const std::string& to)
{
std::string out = in;
std::size_t pos = 0;
while ((pos = out.find(from, pos)) != std::string::npos)
{
out.replace(pos, from.length(), to);
pos += to.length();
}
return out;
}
std::string oldstr = "SyDatoloo";
std::string newstr = replace(oldstr, "a", "n");
std::cout << newstr; // > SyDntoloo