View Compilation Error

0_0_23287162_24745.cpp: In function 'int main()':
0_0_23287162_24745.cpp:6:15: error: 'scanf' was not declared in this scope
  scanf("%d",&n);
               ^
0_0_23287162_24745.cpp:18:17: error: 'printf' was not declared in this scope
  printf("%d",sum);
                 ^