Question

Hi I am trying to remove all numbers that are divisible by two from the arrayList.The probleme is that after one element is removed I get an InvalidOperationException.

   private ArrayList RemoveDivTwo(ArrayList list) {
        int count = 0;
        foreach(int i in list){
            if ((i > 2) && (i % 2 == 0)) {
                list.RemoveAt(count); 
            }
            count++;
        }

        return list;
    }

How can I solve this problem so I wont’t get an exception and be able to remove all elements divisible by two?

Answer 1

Try iterating over it this way.

for(int i = 0; i < list.Count(); i++){
   if ((list[i] > 2) && (list[i] % 2 == 0)) {
                list.RemoveAt(i); 
                i--; //as offsets have shifted by one due to removal
            }
}

You are no longer iterating over the list. So this should work.