View Compilation Error

0_0_29160345_8855.cpp: In function 'int main(int, char**)':
0_0_29160345_8855.cpp:10:28: error: 'scanf' was not declared in this scope
         while(scanf("%d",&n)>0 && n !=0){
                            ^
0_0_29160345_8855.cpp:23:35: error: 'printf' was not declared in this scope
                 printf("%.1f\n",s2);
                                   ^