CODEWITHSUNDEEP
javaswap
Mona Jalal
Mona Jalal

Reputation: 38155

Why do I get an error for swap when the two values are equal in Java?

I am not sure why I get this error and do not know how to solve it. I am getting a Runtime Exception:

for(int j = 0; j < instances[maxInstance].length; j++){

                            centroids[orphanCentroid][j]=instances[maxInstance][j];

                       }

                           for(int j = 0; j < instances[maxInstance].length; j++){
                                {
                                double temp = centroids[maxInstance][j] ;
                                centroids[maxInstance][j] = centroids[orphanCentroid][j] ;
                                centroids[orphanCentroid][j] = temp ;

                           }

Error is:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 5
    at kmeans.KMeans.cluster(KMeans.java:75)
    at kmeans.HW1.main(HW1.java:36)

And it happens at this line:

  double temp = centroids[maxInstance][j] ;

Upvotes: 0

Views: 60

Answers (2)

Steven
Steven

Reputation: 525

This can go either way, without additional information I can't really tell which one is out of bounds.

Case 1: centroids.length < maxInstance

In that case you simply can't access centroids[maxInstance], If you define them as 

instances[10];
centroids[5];
int maxInstance = 5;

Potential solution: Check the size of instances.length and make sure centroids.length <= instances.length

Case 2: index j is out of bounds

Assuming centroids.length <= instances.length is true. Then you need to check whether instances[maxInstance].length > centroids[maxInstance].length Imaging where you define them as 

new instances[maxInstance][10];
new centroids[maxInstance][5];

Then you will get java.lang.ArrayIndexOutOfBoundsException: 5 when you try to access 

j=5; 
centroids[maxInstance][5]

Potential solution:

for(int j = 0; j < centroids[maxInstance].length; j++){ //replace with centroids

Upvotes: 0

dimitris93
dimitris93

Reputation: 4273

I think you need 

for(int j = 0; j < centroids[maxInstance].length; j++){

}

on your second for loop.

Upvotes: 2

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