foo.cc: In function ‘int main()’:
foo.cc:12:26: warning: ‘v’ may be used uninitialized [-Wmaybe-uninitialized]
   12 |                         v++;
      |                         ~^~
foo.cc:6:17: note: ‘v’ was declared here
    6 |         int a,c,v,b;
      |                 ^
foo.cc:14:26: warning: ‘b’ may be used uninitialized [-Wmaybe-uninitialized]
   14 |                         b++;
      |                         ~^~
foo.cc:6:19: note: ‘b’ was declared here
    6 |         int a,c,v,b;
      |                   ^