View Compilation Error

0_0_31283892_26360.cpp: In function 'int main()':
0_0_31283892_26360.cpp:12:4: error: 'sum' was not declared in this scope
    sum+=i;
    ^
0_0_31283892_26360.cpp:14:11: error: 'sum' was not declared in this scope
   cout << sum << endl;
           ^