/in/foo.cc: In function 'int main()':
/in/foo.cc:64:7: warning: unused variable 'k1' [-Wunused-variable]
   int k1 = A.BinSearch2(0, n-1, x);
       ^~
/in/foo.cc: In member function 'int IntArray::BinSearch2(int, int, int)':
/in/foo.cc:38:2: warning: control reaches end of non-void function [-Wreturn-type]
  }
  ^