/in/foo.c: In function 'main':
/in/foo.c:9:16: warning: 'r' is used uninitialized [-Wuninitialized]
    9 |         while(r>0)
      |               ~^~
/in/foo.c:8:13: note: 'r' was declared here
    8 |         int r;
      |             ^