llvm/clang-tools-extra/docs/clang-tidy/checks/modernize/use-starts-ends-with.rst

.. title:: clang-tidy - modernize-use-starts-ends-with

modernize-use-starts-ends-with
==============================

Checks for common roundabout ways to express ``starts_with`` and ``ends_with``
and suggests replacing with the simpler method when it is available. Notably, 
this will work with ``std::string`` and ``std::string_view``.

.. code-block:: c++

  std::string s = "...";
  if (s.find("prefix") == 0) { /* do something */ }
  if (s.rfind("prefix", 0) == 0) { /* do something */ }
  if (s.compare(0, strlen("prefix"), "prefix") == 0) { /* do something */ }
  if (s.compare(s.size() - strlen("suffix"), strlen("suffix"), "suffix") == 0) {
    /* do something */
  }
  if (s.rfind("suffix") == (s.length() - 6)) {
    /* do something */
  }

becomes

.. code-block:: c++

  std::string s = "...";
  if (s.starts_with("prefix")) { /* do something */ }
  if (s.starts_with("prefix")) { /* do something */ }
  if (s.starts_with("prefix")) { /* do something */ }
  if (s.ends_with("suffix")) { /* do something */ }
  if (s.ends_with("suffix")) { /* do something */ }