Authors:
Stuart Reges, Marty Stepp
Chapter:
Arraylists
Exercise:
Exercises
Question:2 | ISBN:9780136091813 | Edition: 2
Question
Write a method called swapPairs that switches the order of values in an ArrayList of String s in a pairwise fashion. Your method should switch the order of the first two values, then switch the order of the next two, then the next two, and so on. If the number of values in the list is odd, the method should not move the final element. For example, if the list initially stores (“to”, “be”, “or”, “not”, “to”, “be”, “hamlet”), your method should change the list’s contents to (“be”, “to”, “not”, “or”, “be”, “to”, “hamlet”).
Answer
Implementation of swapPairs method:
public static void swapPairs(ArrayList strList)
{
for(int i = 0; i < strList.size() - 1; i += 2)
{
String temp1 = strList.get(i);
String temp2 = strList.get(i + 1);
strList.set(i, temp2);
strList.set(i + 1, temp1);
}
}