No of days between 2 dates - excel

Question

In the sample data I have employee wise tour dates with month break up sorted by dates in ascending order. I would like to calculate days. Any formula suggestion please?
Conditions:
1. 1 date for 1 month and 1 employee
2. Should include start date also.
From the below example I may explain my requirement for one employee no.1531. All my dates are in DD/MM/YYYY format.
| 1531 | 3-4-2018 | 3-4-2018 | 4 |
| 1531 | 3-4-2018 | 4-4-2018 | 4 |
| 1531 | 3-4-2018 | 7-4-2018 | 4 |
| 1531 | 22-4-2018 | 2-5-2018 | 4 |
| 1531 | 3-5-2018 | 4-5-2018 | 5 |
| 1532 | 1-4-2018 | 2-4-2018 | 4 |
| 1532 | 22-4-2018 | 2-5-2018 | 4 |
| 1532 | 3-5-2018 | 4-5-2018 | 5 |
1531 employee were started his tour on 03/04/2018 and concluded on the same day for one location. Again he started on the same day 03/04/2018 and concluded on 04/04/2018 for 2nd location. Again the person mentioned he started on 03/04/2018 and concluded on 07/04/2018 for another location. In the above said the date 03/04/2018 were entered trice which was not right, but because I don't have control to stop this in application the entries were made by employee wrongly. So I want excel to consider the date 03/04/2018 as one time only while calculating days. I was tried my best to arrive the days but could not. I have attached my formula as separate file for your kind reference. Kindly look into this and give solution. Even this formula i got through from one among the stack overflow member only. In this i was not comfortable to get my dynamic starting date.
I have asked the similar question earlier also but i have not received any answer against my expectations

Answer 1

Try to do Date 1 - Date 2. Most libraries in most languages should have the - operator overridden.
If not, convert both dates to epoch timestamps(seconds) and then divide it by (24*60):
Date Date1 = new Date(03/04/2018);
Date Date2 = new Date(04/04/2018);
int days = (Date2.toTimeStamp() - Date1.toTimeStamp()) / (24*60);