CODEWITHSUNDEEP
javaarraylist
Tloz
Tloz

Reputation: 339

Trying to add an arraylist

Im adding all the numbers between 0 and 1000 which are multiples or 3 and 5. Im just having trouble adding them up. I keep on getting the error message: Exception in thread "main" java.lang.IndexOutOfBoundsException: Index: 468, Size: 468

My Code 

    //Multiple of 3 and 5 up to 1000
    int total = 0;
    int answer = 0;
    ArrayList<Integer> multof3 = new ArrayList<Integer>();
    for(int i =0; i <=1000; i++){

        if(i % 3 == 0 || i % 5==0){
            multof3.add(i);
            total++;

        }else{
            continue;
        }

    }

    System.out.println(multof3);
    System.out.println(total);

    //looping through array to get sum of elements
    for(int x =0; x <= multof3.size(); x++){
        answer= answer + multof3.get(x);
    }
    System.out.println(answer);

Anyone know the reason why? I cant understand why its not working. It prints out the arraylist so surely I should add the elements together...

Upvotes: 2

Views: 90

Answers (4)

cogle
cogle

Reputation: 1079

which uses just < instead of <=:

for(int x =0; x < multof3.size(); x++){
    answer= answer + multof3.get(x);
}

Upvotes: 0

splrs
splrs

Reputation: 2432

You're trying to access the element beyond the final one in the ArrayList. Change

for(int x =0; x <= multof3.size(); x++){

to

for(int x =0; x < multof3.size(); x++){

Upvotes: 0

Christian Tapia
Christian Tapia

Reputation: 34146

Change the for condition <= to <:

for (int x = 0; x < multof3.size(); x++) {
    answer = answer + multof3.get(x);
}

Remember index starts in 0.

Upvotes: 0

Vincent Ramdhanie
Vincent Ramdhanie

Reputation: 103135

When looping through an array you have to keep in mind that it is indexed from 0.

  for(int x =0; x < multof3.size(); x++){
    answer= answer + multof3.get(x);
  }

If there are 468 items in the list then size() will return 468 but the last item is at index 467. Using the enhanced for loop can help avoid this type of problem:

  for(Integer i: multof3){
       answer += i;
  }

Upvotes: 3

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