faisalazam / daysdifferencecalculator

Command line application to calculate the difference (in days) between provided date strings.

DaysDifferenceCalculator

Date Calculator: Problem Description

Command line application (built using JAVA 20) for calculating the number of full days elapsed between start and end dates.

The first and last days are considered partial days and are never counted.

Following this logic, an experiment that has run from 1972-11-07 to 1972-11-08 should return 0, because there are no fully elapsed days contained in between those dates.

And 2000-01-01 to 2000-01-03 should return 1.

The solution needs to cater to all valid dates between 1901-01-01 and 2999-12-31.

This is a command line based system with at least one way of providing input and output on the terminal.

No libraries should be used to build this solution.

Although any dates specified within the valid date range listed above should work, here are a few test cases to validate the output of your program.

TEST CASES

1. 1983-06-02 – 1983-06-22: 19 days
2. 1984-07-04 – 1984-12-25: 173 days
3. 1989-01-03 – 1983-08-03: 1979 days

Steps to test:

1. Java 20 and maven should be installed on the system
2. Download the project code
   • Either by git clone [email protected]:faisalazam/DaysDifferenceCalculator.git
   • Or by git clone https://github.com/faisalazam/DaysDifferenceCalculator.git
   • Or by downloading the zip file from https://github.com/faisalazam/DaysDifferenceCalculator/archive/refs/heads/master.zip
3. Navigate to the project folder/directory
4. Package/generate the jar file by executing mvn clean package command from terminal
5. Then execute java -jar target/DaysDifferenceCalculator-1.0-SNAPSHOT.jar command from terminal to see it in action :)
6. In order to use this code with some IDE,
   • mvn idea:idea command can be executed for Intellij,
   • mvn eclipse:eclpise command can be executed for Eclipse.

Running tests from IDE

I guess, since Java 17, we need to add the following to VM options in order to use reflection.

pom.xml has already been updated accordingly, but don't forget to add the following to VM options if the runner class is using reflection and you are running the runner class/test from IDE:

--add-opens java.base/java.lang=ALL-UNNAMED --add-opens java.base/java.lang.reflect=ALL-UNNAMED

Application's Demo