View Compilation Error

0_0_34041515_5215.cpp: In function 'int G(int)':
0_0_34041515_5215.cpp:20:15: error: 'p' was not declared in this scope
  for (int i = p; i <= q; i++) {
               ^
0_0_34041515_5215.cpp:20:23: error: 'q' was not declared in this scope
  for (int i = p; i <= q; i++) {
                       ^