View Compilation Error

0_0_16849512_4000.cpp: In function 'int main()':
0_0_16849512_4000.cpp:4:15: error: 'scanf' was not declared in this scope
  scanf("%d",&n);
               ^
0_0_16849512_4000.cpp:12:23: error: 'printf' was not declared in this scope
      printf("%d\n",sum);
                       ^