Java Arrays Index out of Bounds

Question

I'm just starting a unit in Arrays and I was given some example code to look off of for this very basic introductory program for Arrays. Essentially all I have to do is make two arrays that ask for the temperature for that day of the week. After collecting the info it will simply spit it back out in a string like this.

The temperature on Monday was 16 degrees

The temperature on Tuesday was 18 degrees

... etc.

From what I understood from the example code I received I am doing everything correctly. But when try to run the program (in Netbeans) I get this error.

"Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 7 at temperatures.Temperatures.main(Temperatures.java:27) Java Result: 1"

Here is the code:

public static void main(String[] args)throws IOException {
        // TODO code application logic here
        BufferedReader br = new BufferedReader (new InputStreamReader (System.in));
        String temp[]= new String[7];
        String day[]= new String[7];
        day[1]=("Monday");
        day[2]=("Tuesday");
        day[3]=("Wednesday");
        day[4]=("Thursday");
        day[5]=("Friday");
        day[6]=("Saturday");
        day[7]=("Sunday");
        for (int i=0; i <7; i++){
            System.out.println("Please enter the temperature for" + day[i]);
            temp[i]=br.readLine();
        }
        for (int i=0; i <7; i++){
        System.out.println("The high temperature on " + day[i]+ " was "+ temp[i]);
        }
    }
}

kentcdodds · Accepted Answer · 2012-05-17 18:01:34Z

6

Arrays begin at zero (<- that's a link to an article which explains why). So assigning your first value as day[1]=("Monday"); is the issue, it should be day[0]=("Monday"); Hope that helps

answered May 17, 2012 at 18:01

kentcdodds

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2 Comments

Dave555 Over a year ago

Ahh Okay, I had a feeling it would be something like a minor logical error. I re-ran the program, replacing the array numbers and it worked. Thanks!

kentcdodds Over a year ago

Welcome to Stack Overflow :) I'm glad you figured it out! Please accept the answer you feel answered your question in the best way (click the little check mark below the voting arrows) so future comers with similar questions will know what solved your problem.

Affe · Accepted Answer · 2012-05-17 18:01:19Z

4

Arrays in Java start at position 0, not position 1. So if you initialize it to a size of 7, Monday is 0 and Sunday is 6. There is no index 7 available.

answered May 17, 2012 at 18:01

Affe

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Comments

hekomobile · Accepted Answer · 2012-05-17 18:04:18Z

1

The arrays starter in 0,

try this

    day[0]=("Monday");
    day[1]=("Tuesday");
    day[2]=("Wednesday");
    day[3]=("Thursday");
    day[4]=("Friday");
    day[5]=("Saturday");
    day[6]=("Sunday");

and should you change this loop

for(int i=0; i < 7; i++){
        System.out.println("Please enter the temperature for" + day[i]);
        temp[i]=br.readLine();
    }

for this

for(int i=0; i < day.length(); i++){
        System.out.println("Please enter the temperature for" + day[i]);
        temp[i]=br.readLine();
    }

I hope help you.

answered May 17, 2012 at 18:04

hekomobile

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1 Comment

kentcdodds Over a year ago

Watch out, this was tagged with homework. We don't want to give someone the answer explicitly, just point them in the right direction.

PeakGen · Accepted Answer · 2012-05-17 18:06:21Z

0

That is because your array starts from 1, ends from 7. If your array length is 7, the last index should be one less than tyhe array length. In your case, array sees that you have declared it for 7 elements, but inserted 8 positions. So, start array from 0, end it from 6

answered May 17, 2012 at 18:06

PeakGen

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Comments

Theja · Accepted Answer · 2012-06-20 12:15:57Z

0

If an Array is is 'N' then the boundaries of that array is 0 and "N-1". In your case the array Boundaries are 0 and 6. But you are tring to write value into array[7] which is not exists.

answered Jun 20, 2012 at 12:15

Theja

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