/in/foo.c: In function 'main':
/in/foo.c:39:26: warning: 'c' may be used uninitialized [-Wmaybe-uninitialized]
   39 |                         c=c+1;
      |                         ~^~~~
/in/foo.c:7:13: note: 'c' was declared here
    7 |         int c;//总和
      |             ^