View Compilation Error

0_0_33709669_21433.cpp: In function 'int main()':
0_0_33709669_21433.cpp:3:18: error: 'scanf' was not declared in this scope
     scanf("%d",&n);
                  ^
0_0_33709669_21433.cpp:11:28: error: 'printf' was not declared in this scope
         printf("%d\n\n",sum);
                            ^