How do I create a program to calculate the average age and salary of the personnel.

So for the Program, we have to build a program to calculate the average age and salary of the Personnel.

Here is my code:

    #include <iostream>
    using namespace std;

     struct Personnel {
     int average_Age;
     float salary;
     };
     int main()
     {
     Personnel p1;
     cout << "Enter age :";
     cin >> p1.average_Age;
     cout << "Enter salary:";
     cin >> p1.salary;


      int year = 0;
      float Salary, tax ;

      if (Salary <= 40000)
      {
      cout << "What is the Salary";
      cin >> Salary
      year = year + 1;
      Salary = Salary+ year - tax; 
      }  

      }

where else can I go with my code or would you suggest I redo it all?