View Compilation Error

0_0_38064108_25494.cpp: In function 'int main()':
0_0_38064108_25494.cpp:52:28: error: 'i' was not declared in this scope
   if (((ll) (size[1] - top[i]) * (size[1] - top[i] - 1) >> 1) < 0) while (1);
                            ^