View Compilation Error

0_0_28371258_16614.cpp: In function 'int main()':
0_0_28371258_16614.cpp:5:22: error: 'scanf' was not declared in this scope
  while(~scanf("%d",&n)) {
                      ^
0_0_28371258_16614.cpp:7:22: error: 'printf' was not declared in this scope
    printf("%d\n",a[n]);
                      ^