/in/foo.c: In function 'dat':
/in/foo.c:109:3: warning: value computed is not used [-Wunused-value]
   *yy++;
   ^~~~~
/in/foo.c: In function 'lea':
/in/foo.c:116:20: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
  if ((ly % 4 == 0) && (ly % 100 != 0) || (ly % 400 == 0))
      ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~