I think my logic is correct but i dont know how to make it work.

Question about the task

CRUD

Java Core, Level 7, Lesson 10

Resolved

I never worked with main(String[] args) before! Help will be apreciated, thanks!

CrUD: Create, Update, Delete.

The program runs with one of the following sets of arguments:
-c name sex bd -u id name sex bd -d id -i id

Argument values:
name (String)
sex ("m" or "f")
bd (birth date in the following format: "04 15 1990")
-c (adds a person with the specified arguments to the end of allPeople; displays the id on the screen)
-u (updates the data of the person with the specified id)
-d (performs the logical deletion of the person with the specified id; replaces all of its data with null)
-i (displays information about the person with the specified id: name sex (m/f) bd (format Apr 15 1990))

The id corresponds to the index in the list.
All the people should be stored in allPeople.
Use Locale.ENGLISH as the second argument for SimpleDateFormat.

Example arguments:
-c Washington m "04 15 1990"

Example output for the -i argument:
Washington m Apr 15 1990

Requirements:

The Solution class must contain a public static List<Person> field called allPeople.
The Solution class must have a static block where two people are added to the allPeople list.
When you start the program with the -c argument, the program should add the person with the specified arguments to the end of the allPeople list and display the id (index).
When you run the program with the -u argument, the program must update the data of the person with the specified id in the allPeople list.
When you run the program with the -d argument, the program must perform the logical deletion the person with the specified id in the allPeople list.
When you run the program with the -i argument, the program should display the data about the person with the specified id in accordance with the format given in the task.

package com.codegym.task.task17.task1710; import java.text.DateFormat; import java.util.ArrayList; import java.util.Date; import java.util.List; /* CRUD */ public class Solution { public static List<Person> allPeople = new ArrayList<>(); static { allPeople.add(Person.createMale("Donald Chump", new Date())); // id=0 allPeople.add(Person.createMale("Larry Gates", new Date())); // id=1 } public static void main(String[] args) { // Start here if(args[0].equals("-c")){ if(args[2].equals(Sex.MALE)){ allPeople.add(Person.createMale(args[1],new Date(args[3]))); System.out.println(allPeople.size()); } else if(args[2].equals(Sex.FEMALE)){ allPeople.add(Person.createFemale(args[1],new Date(args[3]))); System.out.println(allPeople.size()); } } else if(args[0].equals("-u")){ allPeople.get(Integer.parseInt(args[1])).setName(args[2]); allPeople.get(Integer.parseInt(args[1])).setBirthDate(new Date(args[4])); if(args[3].equals(Sex.MALE)){ allPeople.get(Integer.parseInt(args[1])).setSex(Sex.MALE); } else if(args[3].equals(Sex.FEMALE)){ allPeople.get(Integer.parseInt(args[1])).setSex(Sex.FEMALE); } } else if(args[0].equals("-d"))allPeople.remove(Integer.parseInt(args[1])); else if(args[0].equals("-i")){ System.out.println(allPeople.get(Integer.parseInt(args[1])).getName()+" "+allPeople.get(Integer.parseInt(args[1])).getSex()+" "+ allPeople.get(Integer.parseInt(args[1])).getBirthDate()); } } }

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Guadalupe Gagnon

Level 37 , Tampa, United States

24 January 2019, 15:21

useful

#1 In your -c if block, you are checking for Sex.MALE and Sex.FEMALE. The inputs however are 'm' or 'f'. I see that duplicated in the -u if block. #2 The Id is the index number of the person in the list, you only print the size of the list. when you enter a person in a list of 5 people, their corresponding ID will be 4, not 5. #3 You also are not able to set a Date with just a string. Try using a SimpleDateFormat to parse the date string and then use that to set the date: https://docs.oracle.com/javase/8/docs/api/java/text/SimpleDateFormat.html #4 Logical deletion stumped me too. So you do not actually remove the person, you just set all their values (name, sex, birthday) to null. #5 The display information only displays the name using getName. I sovled this by overiding toString in the person class to display name sex and dirthdate. Remember to overide toString in the sex class to display either m or f. Also remember to create a simplaDateFormat to display the birthday in the proper format. ------------------------------------------------------------------------------------------------------------------------------------------ You can right click on solution (on the left packages bar) and select "create 'Sloution.main()'. In the box that pulls up you can add program arguments for purposes of testing. See picture: . .

anotherLearner

Level 18 , Barcelona, Catalunya

24 January 2019, 17:22

Thank you very much Guadalupe. You are right in everything, all this is something that I wanted to solve after I could run the program. It throws an Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0 at com.codegym.task.task17.task1710.Solution.main(Solution.java:23) Its the first line of my code so i dont know if im building it correctly. Its my first time working with args like that. Help will be apreciated, thanks!

anotherLearner

Level 18 , Barcelona, Catalunya

24 January 2019, 17:26

Also I dont have Create "..." option, any tip?

Guadalupe Gagnon

Level 37 , Tampa, United States

24 January 2019, 17:47

the exception being thrown is because no arguments have been passed in to your code as of yet: args.length = 0 Are you right-clicking on 'solution' on the left side (you can see it highlighted behind the right click bar in my picture). You can also add them from the file bar: Run>Edit Configurations. A similar window will pop up and you can add program arguments that will be accessible through args. This window takes a little tinkering to get used to it, but it only took me a few lessons to get the hang of it enough to complete tasks.

anotherLearner

Level 18 , Barcelona, Catalunya

24 January 2019, 18:00

Run>Edit Cinfigurations worked for me, ill try to get used to it. Thanks too much Guadalupe!

Guadalupe Gagnon

Level 37 , Tampa, United States

24 January 2019, 18:01

Good luck!