View Compilation Error

0_0_19215311_7232.cpp: In function 'int main()':
0_0_19215311_7232.cpp:47:21: error: 'scanf' was not declared in this scope
  while(scanf("%d",&n)!=-1)
                     ^
0_0_19215311_7232.cpp:72:23: error: 'printf' was not declared in this scope
   printf("%I64d\n",ans);
                       ^