foo.cc: In function ‘int main()’:
foo.cc:15:18: warning: ‘c’ may be used uninitialized [-Wmaybe-uninitialized]
   15 |                 c=a+b;
      |                 ~^~~~
foo.cc:5:19: note: ‘c’ was declared here
    5 |         int n,a,b,c,i;
      |                   ^