View Compilation Error

0_0_38119747_26336.cpp: In function 'int main()':
0_0_38119747_26336.cpp:9:22: error: 'scanf' was not declared in this scope
   while(scanf("%d",&n)==1){
                      ^
0_0_38119747_26336.cpp:15:24: error: 'printf' was not declared in this scope
     }printf("%d\n",a[n]);
                        ^