View Compilation Error

0_0_39466873_2971.cpp: In function 'int main()':
0_0_39466873_2971.cpp:5:15: error: 'cin' was not declared in this scope
    5 |         while(cin>>hex>>a>>b){
      |               ^~~
0_0_39466873_2971.cpp:2:1: note: 'std::cin' is defined in header '<iostream>'; did you forget to '#include <iostream>'?
    1 | #include<iomanip>
  +++ |+#include <iostream>
    2 | using namespace std;
0_0_39466873_2971.cpp:8:25: error: 'cout' was not declared in this scope
    8 |                         cout<<"-";
      |                         ^~~~
0_0_39466873_2971.cpp:8:25: note: 'std::cout' is defined in header '<iostream>'; did you forget to '#include <iostream>'?
0_0_39466873_2971.cpp:12:21: error: 'cout' was not declared in this scope
   12 |                     cout<<hex<<uppercase<<sum<<endl;
      |                     ^~~~
0_0_39466873_2971.cpp:12:21: note: 'std::cout' is defined in header '<iostream>'; did you forget to '#include <iostream>'?