單鏈表

迭代的意思是讓計算機對一組指令進行重複執行，在每次執行這組指令時，都從變數的原值推出它的一個新值。

遞迴是在其定義或說明中有直接或間接呼叫自身的一種方法。

public class SinglyListLength {    Node head;  // head of list    class Node {        int data;        Node next;        Node(int d) {            data = d;            next = null;        }    }    // Returns count of nodes in linked list.    // 迭代    public int getCount() {        Node temp = head;        int count = 0;        while (temp != null) {            count++;            temp = temp.next;        }        return count;    }    // 遞迴    public int getCountRecursive(Node node) {        if (node == null)            return 0;        return 1 + getCountRecursive(node.next);    }    public void push(int data) {        Node node = new Node(data);        node.next = head;        head = node;    }    public static void main(String[] args) {        SinglyListLength list = new SinglyListLength();        for (int i = 0; i < 5; i++)            list.push(i);        System.out.println("Count using iterative is "                + list.getCount());        System.out.println("Count using recursive is "                + list.getCountRecursive(list.head));    }}

輸出

Count using iterative is 5Count using recursive is 5