foo.cc: In function ‘int main()’:
foo.cc:18:23: warning: ‘c’ may be used uninitialized [-Wmaybe-uninitialized]
   18 |                 cout<<c;
      |                       ^
foo.cc:5:19: note: ‘c’ was declared here
    5 |         int k,a,b,c;
      |                   ^