View Compilation Error

0_0_20396654_24546.cpp: In function 'int main(char*)':
0_0_20396654_24546.cpp:11:8: error: 'sum' was not declared in this scope
        sum += i;
        ^
0_0_20396654_24546.cpp:12:21: error: 'sum' was not declared in this scope
     printf("%d\n\n",sum);
                     ^