View Compilation Error

0_0_22849651_21653.cpp: In function 'int main()':
0_0_22849651_21653.cpp:7:22: error: 'scanf' was not declared in this scope
  while (scanf("%d",&n)==1) {
                      ^
0_0_22849651_21653.cpp:8:13: error: 'cout' was not declared in this scope
   if (n > 3)cout << solveANum(n) << endl;
             ^
0_0_22849651_21653.cpp:8:37: error: 'endl' was not declared in this scope
   if (n > 3)cout << solveANum(n) << endl;
                                     ^
0_0_22849651_21653.cpp:9:8: error: 'cout' was not declared in this scope
   else cout << n << endl;
        ^
0_0_22849651_21653.cpp:9:21: error: 'endl' was not declared in this scope
   else cout << n << endl;
                     ^