View Compilation Error

0_0_24445288_384.cpp: In function 'int main()':
0_0_24445288_384.cpp:12:25: error: 'scanf' was not declared in this scope
     while(scanf("%lf",&n))
                         ^
0_0_24445288_384.cpp:52:28: error: 'printf' was not declared in this scope
         printf("%.3lfn",sum);
                            ^