Center text in a fixed-width field using C++

center.cpp

#include "C:\gsl\narrow" // path to GSL include files
#include <string>

/***
 * Center text in a fixed-width field
 * https://stackoverflow.com/questions/14861018/center-text-in-fixed-width-field-with-stream-manipulators-in-c
 */
std::string center(const std::string& text, int width)
{
  /***
   * FIX: fixed-size type, uint64_t, resolves C4365, type mismatch with reserve and append
   * FIX: gsl::narrow_cast resolves warning about unsafe static_cast usage, requires GSL library
   */
  const uint64_t len = gsl::narrow_cast<uint64_t>(text.length());
  // const uint64_t len = static_cast<uint64_t>(text.length());
  const uint64_t padding = width - len;
  const uint64_t paddingLeft = padding / 2;
  const uint64_t paddingRight = padding - paddingLeft;

  std::string result;
  result.reserve(static_cast<uint64_t>(width));

  result.append(paddingLeft, ' ');
  result.append(text);
  result.append(paddingRight, ' ');

  return result;
}