Pros:
- it is convenient to type and read numbers this way;
- Ada, Perl, C++, Go and Rust already support that;
- can support thousands as well as lakhs and crores;

Cons:
- standard SQL does not have this support;
- PostgreSQL treat `SELECT 1_000_000` as number one with `_000_000` alias: http://sqlfiddle.com/#!17/0a28f/400
- C++ has `1'000'000` instead of `1_000_000`;

What do you think?

#pragma once
#include <string>
#include <cstring>
#include <cstddef>
#include <cstdint>
#include <type_traits>
namespace detail
{
    bool startsWith(const std::string & s, const char * prefix, size_t prefix_size);
    bool endsWith(const std::string & s, const char * suffix, size_t suffix_size);
}
inline bool startsWith(const std::string & s, const std::string & prefix)
{
    return detail::startsWith(s, prefix.data(), prefix.size());
}
inline bool endsWith(const std::string & s, const std::string & suffix)