Calculate a **running total** of positive integer values using a while loop and a boolean flag that will test for the condition of a **sentinel value**.
- You will use the concept of a running total and sum up a series of inputed values together until the **sentinel value** of (-1) is entered.
- Validate that each inputed value is positive, otherwise have the user re-enter a positive value until valid.
- Once the sentinel value is entered, you will output the `max`, `min`, and `average` with precision up to 2 decimal places (remember not to include the sentinel value (-1) as an inputed value with your calculations).
- You will need to use the **iomanip** library for decimal precision (`setprecision` output modifier).
- You will also need a counter variable to count the number of values inputed.
Example Output
```
Please enter an integer: 1 [entered]
Please enter an integer: 2 [entered]
Please enter an integer: 3 [entered]
Please enter an integer: -1[entered]
Min: 1
Max: 3
Total: 6
Avg: 2.00
```
