View Compilation Error

0_0_39845580_18540.cpp: In function 'int main()':
0_0_39845580_18540.cpp:8:12: error: 'cin' was not declared in this scope
    8 |     while (cin >> a) {
      |            ^~~
0_0_39845580_18540.cpp:3:1: note: 'std::cin' is defined in header '<iostream>'; did you forget to '#include <iostream>'?
    2 | #include <cmath>
  +++ |+#include <iostream>
    3 | using namespace std;