/in/foo.cc: In function 'int main()':
/in/foo.cc:6:11: warning: 'c' is used uninitialized in this function [-Wuninitialized]
     l=2*(c+k);
         ~~^~~
/in/foo.cc:6:11: warning: 'k' is used uninitialized in this function [-Wuninitialized]