/in/foo.cc: In function 'int main()':
/in/foo.cc:4:6: warning: unused variable 'k' [-Wunused-variable]
  int k=0;
      ^
/in/foo.cc:25:8: warning: 'b' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<b<<endl;
        ^