View Compilation Error

0_0_19216530_1459.cpp: In function 'int main()':
0_0_19216530_1459.cpp:43:21: error: 'scanf' was not declared in this scope
  while(scanf("%d",&n)!=EOF)
                     ^
0_0_19216530_1459.cpp:43:24: error: 'EOF' was not declared in this scope
  while(scanf("%d",&n)!=EOF)
                        ^
0_0_19216530_1459.cpp:56:23: error: 'printf' was not declared in this scope
    printf("%d ",ans[i]);
                       ^
0_0_19216530_1459.cpp:57:23: error: 'printf' was not declared in this scope
   printf("%d\n",ans[i]);
                       ^