View Compilation Error

0_0_39089888_12935.cpp: In function 'int main()':
0_0_39089888_12935.cpp:14:9: error: 'sum' was not declared in this scope
   14 |         sum += i;
      |         ^~~
0_0_39089888_12935.cpp:16:18: error: 'sum' was not declared in this scope
   16 |     std::cout << sum << "\n";
      |                  ^~~