View Compilation Error

0_0_36127470_17394.cpp: In function 'int main()':
0_0_36127470_17394.cpp:5:15: error: 'scanf' was not declared in this scope
  scanf("%d",&n);
               ^
0_0_36127470_17394.cpp:14:19: error: 'printf' was not declared in this scope
  printf("%d\n",sum);
                   ^