foo.cc: In function ‘int main()’:
foo.cc:13:25: warning: ‘c’ may be used uninitialized [-Wmaybe-uninitialized]
   13 |                 while (c<=e)
      |                        ~^~~
foo.cc:5:20: note: ‘c’ was declared here
    5 |         double a,b,c,e,cnt=2;
      |                    ^