View Compilation Error

0_0_39402388_5210.cpp: In function 'int main()':
0_0_39402388_5210.cpp:13:19: error: 'sum' was not declared in this scope
   13 |                 a[sum]=0;
      |                   ^~~
0_0_39402388_5210.cpp:20:19: error: 'sum' was not declared in this scope
   20 |                 a[sum]=1;
      |                   ^~~