/in/foo.cc: In function 'int main()':
/in/foo.cc:10:19: warning: unused variable 'l' [-Wunused-variable]
  register int i,j,l,r;
                   ^
/in/foo.cc:10:21: warning: unused variable 'r' [-Wunused-variable]
  register int i,j,l,r;
                     ^