/in/foo.cc:125:34: warning: multi-character character constant [-Wmultichar]
  125 |         size_t space = line.find('  ');
      |                                  ^~~~
/in/foo.cc: In lambda function:
/in/foo.cc:125:34: warning: overflow in conversion from 'int' to 'char' changes value from '8224' to '' '' [-Woverflow]
/in/foo.cc: In function 'int main()':
/in/foo.cc:131:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17' [-Wc++17-extensions]
  131 |         auto [x1, k1] = process(line1);
      |              ^
/in/foo.cc:132:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17' [-Wc++17-extensions]
  132 |         auto [x2, k2] = process(line2);
      |              ^