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Question about the task

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The code is correct and It gives the solution too, but I am not able to satisfy all the conditions. why?

Use the keyboard to enter a number representing a day of the week. Then, depending on the entered number, display the name of the day of the week: "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday", if you enter a number greater than 7 or less than 1, display "No such day of the week".

Example for number 5:
Friday

Example for number 10:
No such day of the week

Requirements:

The program should read a number from the keyboard.
The program should display text on the screen.
If you enter a number from 1 to 7, you need to display the name of the day of the week.
If you enter a number outside the range of 1 to 7, then display a notification that there is no such day of the week.

package com.codegym.task.task04.task0413; /* Day of the week */ import java.io.*; public class Solution { public static void main(String[] args) throws Exception { BufferedReader x = new BufferedReader(new InputStreamReader(System.in)); String N = x.readLine(); String M = x.readLine(); int n = Integer.parseInt(N); if(n>0&&n<8){ String day[] = {"Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"}; System.out.println(day[n]); } else System.out.println("No such day of the week");//write your code here } }

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Alexander Hernandez

Level 11 , Logan, United States

16 July 2019, 17:30

You're forgetting the rule of thumb of arrays: All arrays start at index 0, not at index 1. In your array, "Monday" would be index 0, "Tuesday" at index 1, and so on until index 6 which is "Sunday". Your if statement only accepts numbers from 1 to 7; this means "Monday" cannot be printed since its index is 0, and therefore will return false. No such day of the week will be printed instead. Look below for the logic: ------------------------------------------------------------------------------------------------------------------------------------- User inputs 0, stored in the String N; N is converted into a integer, into the int variable n. Conditional Statement Process: Note that n = 0; Is n greater than 0 and less 8? - False; n is equal to 0. Then the else block is run: No such day of the week ------------------------------------------------------------------------------------------------------------------------------------- A similar mistake also impacts with the user inputing 7, which will result in a java.lang.ArrayIndexOutOfBoundsException, because the array only has a index of 1 to 6; not 1 to 7.

GCPix Backend Developer

16 July 2019, 14:30

Are you sure it gives you the correct answer? I can't see any way to print Monday and if you try to print day[7] it should give you an out of bounds error?

hidden #10462592

Level 8

18 July 2019, 03:58

I realized that the array start with 0 instead of 1.. so in order to get the correct day I added a space in the first location. {" ", "Monday", "Tuesday", .... and so on}

GCPix Backend Developer

18 July 2019, 07:24

I would doubt you will pass verification using that. You need to take the user input and change it to match the original array indices. so if someone enters 1, you actually want to search 0. Realistically you can't keep adding a blank into the start of every list you create so that your index works. In this place we use lots of them!

hidden #10462592

Level 8

19 July 2019, 09:02

It passed the verification, also assuming that the week starts from 1 instead of 0, we can agree that the user will enter a number ranging from 1 onwards. Taking that route, I added a blank space in the first spot where the array value is 0. Is there any other way to start count from 1 in an array????

GCPix Backend Developer

22 July 2019, 10:24

The index will always start from 0. inside the for() block you can loop from i=1 if you want but you will have to adjust everything else so that it looks at the correct index to return the value. Otherwise I would just have them enter a number from 1-7 but tell it to look at arr[n-1], n being their number. I can't remember when it comes in the course but you will get to other types of lists where you can set a key of 1 and then the value is "Monday" for instance which will get you round that. I don't use arrays in for most things because I cannot dynamically change the size. (I have done a little bit of Java separate from this course)

hidden #10462592

Level 8

24 July 2019, 14:33

Ooo, that's cool. Setting the for loop to start from 1 is much sensible actually. So even though we don't mention the size of the array you are suggesting we can not use it to dynamically change size? In C++ we mention the size of an array or else the array can be used dynamically. It'll readily take values from the user and store in the array. I will anyways look into it. Thanks! Tell me more about these different types of lists. How can we use them? Where can I find it?

GCPix Backend Developer

25 July 2019, 07:22

An Array here is an absolute size, if it was full and you wanted to add something else you would have to create a new array with bigger size, copy the original across then add the new thing. An ArrayList basically does that for you (but it will still start from 0 index). There are other types of lists, that are also dynamically sized that will still have an index, if I remember correctly, but you set the key and value. When you get to it in the course (think it is in section 7 or 8) it will explain when you should use them. They can be faster/slower to use depending on what you are trying to do. As well as ArrayList you will be looking for LinkedList, HashMap, HashSet, TreeSet. https://docs.oracle.com/javase/8/docs/api/java/util/Collection.html this link will take you to the Collections java doc, links to the classes that implement them are there.