/in/foo.c: In function 'main':
/in/foo.c:11:12: warning: 'p' may be used uninitialized [-Wmaybe-uninitialized]
   11 |         if (p == 0)
      |            ^
/in/foo.c:5:16: note: 'p' was declared here
    5 |         double p;
      |                ^