View Compilation Error

0_0_38037792_22349.cpp: In function 'int main()':
0_0_38037792_22349.cpp:10:19: error: 'scanf' was not declared in this scope
     scanf("%d", &C);
                   ^
0_0_38037792_22349.cpp:13:30: error: 'printf' was not declared in this scope
         printf("%lld\n", a[n]);
                              ^