View Compilation Error

0_0_39506105_19413.cpp: In function 'int main()':
0_0_39506105_19413.cpp:64:17: error: 'r' was not declared in this scope
   64 |                 r += a[i];
      |                 ^
0_0_39506105_19413.cpp:66:17: error: 'l' was not declared in this scope
   66 |                 l += a[i];
      |                 ^