Java 中的 CopyOnWriteArrayList size()方法

原文:https://www . geeksforgeeks . org/copy onwriterarraylist-size-method-in-Java/

size() 方法返回列表的大小。它返回列表中元素的数量。

语法:

public int size()

参数:函数不接受任何参数。

返回值:函数返回列表的大小。

以下程序说明了上述功能:

程序 1:

// Java Program to illustrate the CopyOnWriteArrayList
// size() method in Java
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.*;

public class GFG {
    public static void main(String[] args)
    {

        // create object of CopyOnWriteArrayList
        CopyOnWriteArrayList<Integer> ArrLis
            = new CopyOnWriteArrayList<Integer>();

        // Add elements
        ArrLis.add(32);
        ArrLis.add(67);
        ArrLis.add(98);
        ArrLis.add(100);

        // print CopyOnWriteArrayList
        System.out.println("CopyOnWriteArrayList: "
                                          + ArrLis);

        // size value print
        System.out.println("size of ArrLis: " 
                              + ArrLis.size());
    }
}

输出:

CopyOnWriteArrayList: [32, 67, 98, 100]
size of ArrLis: 4

程序二:

// Java Program to illustrate the CopyOnWriteArrayList
// size() method in Java
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.*;

public class GFG {
    public static void main(String[] args)
    {

        // create object of CopyOnWriteArrayList
        CopyOnWriteArrayList<String> ArrLis
            = new CopyOnWriteArrayList<String>();

        // Add elements
        ArrLis.add("gopal");
        ArrLis.add("gfg");
        ArrLis.add("jgec");
        ArrLis.add("sudo");

        // print CopyOnWriteArrayList
        System.out.println("CopyOnWriteArrayList: " 
                                          + ArrLis);

        // size value print
        System.out.println("size of ArrLis: " 
                                + ArrLis.size());
    }
}

输出:

CopyOnWriteArrayList: [gopal, gfg, jgec, sudo]
size of ArrLis: 4

参考:https://docs . Oracle . com/javase/8/docs/API/Java/util/concurrent/copy onwriterarraylist . html # size–