java 方法 示例

ArrayDeque類offerFirst()方法 (ArrayDeque Class offerFirst() method)

• offerFirst() Method is available in java.lang package.

  offerFirst()方法在java.lang包中可用。

• offerFirst() Method is used to add the given element at the front of this deque.

  offerFirst()方法用于將給定元素添加到此雙端隊列的前面。

• offerFirst() Method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.

  offerFirst()方法是一種非靜態方法，只能通過類對象訪問，如果嘗試使用類名稱訪問該方法，則會收到錯誤消息。

• offerFirst() Method may throw an exception at the time of adding element in the deque.

  offerFirst()方法在雙端隊列中添加元素時可能會引發異常。

  NullPointerException: This exception may throw when the given element is null exists.

  NullPointerException ：當給定元素為null時，可能引發此異常。

Syntax:

句法：

    public boolean offerFirst(T element);

Parameter(s):

參數：

• T element – represents the element to be inserted at the first position of this deque.

  T element –表示要在此雙端隊列的第一個位置插入的元素。

Return value:

返回值：

The return type of the method is boolean, it returns true if the given element is added at the front of this deque successfully, else it returns false.

該方法的返回類型是布爾值 ，如果給定的元素在此雙端隊列的前面添加成功返回true，否則返回false。

Example:

例：

// Java program to demonstrate the example 
// of boolean offerFirst(T element) method of ArrayDeque 
import java.util.*;
public class OfferFirstOfArrayDeque {
public static void main(String[] args) {
// Creating an ArrayDeque with initial capacity of
// storing elements
Deque<String> d_queue = new ArrayDeque<String>(10);
// By using add() method to add elements
// in ArrayDeque
d_queue.add("C");
d_queue.add("C++");
d_queue.add("Java");
d_queue.add("Php");
d_queue.add("DotNet");
// Display Deque Elements
System.out.println("d_queue before offerFirst(): ");
System.out.println("ArrayDeque Elements = " + d_queue);
System.out.println();
// By using offerFirst() method to add the
// elements at the first position in ArrayDeque
d_queue.offerFirst("Python");
// Display Deque Elements
System.out.println("d_queue after offerFirst(): ");
System.out.println("d_queue.offerFirst() : "+ d_queue);
}
}

Output

輸出量

d_queue before offerFirst(): 
ArrayDeque Elements = [C, C++, Java, Php, DotNet]d_queue after offerFirst(): 
d_queue.offerFirst() : [Python, C, C++, Java, Php, DotNet]

翻譯自: https://www.includehelp.com/java/arraydeque-offerfirst-method-with-example.aspx

java 方法 示例