View Compilation Error

0_0_18727422_13337.cpp: In function 'int main()':
0_0_18727422_13337.cpp:33:24: error: 'scanf' was not declared in this scope
     while(scanf("%d",&n),n)  
                        ^
0_0_18727422_13337.cpp:35:27: error: 'printf' was not declared in this scope
         printf("%d\n",p[n]);  
                           ^