View Compilation Error

0_0_15883827_5071.cpp:2:11: error: '::main' must return 'int'
 void main()
           ^
0_0_15883827_5071.cpp: In function 'int main()':
0_0_15883827_5071.cpp:28:35: error: 'aa' was not declared in this scope
                printf("%d\n",sum);aa
                                   ^