next和hasnext_使用Java中的next（）和hasNext（）方法遍历List元素

next和hasnext

Given a List of integers and we have to traverse, print all its element using next() and hasNext() methods.

给定一个整数列表，我们必须遍历，使用next()和hasNext()方法打印其所有元素。

什么是hasNex()和next()方法？ (What are hasNex() and next() methods?)

Both are the library methods of java.util.Scanner class.

两者都是java.util.Scanner类的库方法。

Method hasNext() returns 'true'/'false' - If collection has more values/elements, it returns true otherwise it returns false.

方法hasNext()返回'true'/'false'-如果collection具有更多的值/元素，则返回true，否则返回false 。

Method next() returns the next element in the collection.

方法next()返回集合中的下一个元素。

Note: In this example, we will create/declare an iterator by specifying Integer type - which is base type of the List and then the methods next() and hasNext() will be called through Iterator object.

注意：在此示例中，我们将通过指定Integer类型(这是List的基本类型)来创建/声明一个迭代器，然后将通过Iterator对象调用 next()和hasNext()方法。

Example:

例：

In this example, we will declare a List of integers, add some of the elements and print the elements by using hasNext() and next() methods.

在此示例中，我们将声明一个整数列表，添加一些元素，然后使用hasNext()和next()方法打印这些元素。

Program:

程序：

import java.util.*;

public class ListExample {
	public static void main (String[] args) {
		//creating a list of integers
		List<Integer> int_list = new ArrayList<Integer> ();
		
		int count=0; //variable to count total traversed elements 

		//adding some of the elements
		int_list.add (10);
		int_list.add (20);
		int_list.add (30);
		int_list.add (40);
		int_list.add (50);

		//printing elements
		System.out.println ("List elements are...");
		//creating iterator
		Iterator<Integer> it = int_list.iterator ();
		while (it.hasNext()){
			System.out.println (it.next());
			count+=1;
		}
		System.out.println ("Total traversed elements are: "+count);
	}
};

Output

输出量

List elements are...
10
20
30
40
50
Total traversed elements are: 5

翻译自: https://www.includehelp.com/java-programs/traverse-the-list-elements-using-next-and-hasnext-methods-in-java.aspx

next和hasnext