/in/foo.cc: In function 'int main()':
/in/foo.cc:42:22: warning: 'rindex' may be used uninitialized in this function [-Wmaybe-uninitialized]
  if(abs(lindex - (n-1-rindex) % 2 != 0))
                  ~~~~^~~~~~~~
/in/foo.cc:42:40: warning: 'lindex' may be used uninitialized in this function [-Wmaybe-uninitialized]
  if(abs(lindex - (n-1-rindex) % 2 != 0))
                                        ^