CODEWITHSUNDEEP
javaarrays
user2895567
user2895567

Reputation:

Can't understand array error

I just read the intro to arrays section in my AP Java book and tried the following example however I get an error and cant understand why.

Code: 

public static void arrayT(int i){
  String[] alphabet = new String[5];
  alphabet[0] = "a";
  alphabet[1] = "c";
  alphabet[2] = "x";
  alphabet[3] = "b";
  alphabet[4] = "d";
  alphabet[5] = "e";
  System.out.println(alphabet[i]);
}

Main: 

public static void main(String [] args){
  arrayT(2);
}

Output: 

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 5
at Main.arrayT(Main.java:18)
at Main.main(Main.java:36)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120)

What am I doing wrong?

Upvotes: 0

Views: 78

Answers (5)

Ashish
Ashish

Reputation: 1941

public static void arrayT(int i){
  String[] alphabet = new String[5];
  alphabet[0] = "a";
  alphabet[1] = "c";
  alphabet[2] = "x";
  alphabet[3] = "b";
  alphabet[4] = "d";
  alphabet[5] = "e";
  System.out.println(alphabet[i]);
}

in this when you declared statement

 String[] alphabet = new String[5];

then ur String Array size is 5 i.e 0-4(including 0 then total is 5 elements can be added)

so u have to increase the size of String array to 6 so as to add 6 elements

 String[] alphabet = new String[6];

Upvotes: 0

Mengjun
Mengjun

Reputation: 3197

This is because you declare the array with length 5 but you assign 6 values to it.

alphabet[5] = "e";. This one causes 'Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 5'

Try to set the length of array with length 6. Then you will get the right result.

String[] alphabet = new String[6];

Upvotes: 0

Dark Knight
Dark Knight

Reputation: 8337

Array defined is of length 5, and with alphabet[5] = "e"; you are trying to add 6'th element to array. Either define array with legnth as 6

String[] alphabet = new String[6];

Or remove last line of code

alphabet[5] = "e"

Upvotes: 0

EJK
EJK

Reputation: 12527

String[] alphabet = new String[5];

The above statement allocates an array with a capacity of 5. Valid indecies are 0, 1, 2, 3, and 4.

Index 5 is out of bounds. Thus:

  alphabet[5] = "e";

throws the exception.

Upvotes: 4

sashkello
sashkello

Reputation: 17871

String[] alphabet = new String[5]; creates an array of length 5, that is it has indexes 0, 1, 2, 3, 4 and exactly five elements in it. You are trying to access an element which isn't there, under index 5.

Upvotes: 1

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