Java Vector用法及代碼示例

// Java Program to Demonstrate Working of Vector
// Via Creating and Using It

// Importing required classes
import java.io.*;
import java.util.*;

// Main class
class GFG {

    // Main driver method
    public static void main(String[] args)
    {
        // Size of the Vector
        int n = 5;

        // Declaring the Vector with
        // initial size n
        Vector<Integer> v = new Vector<Integer>(n);

        // Appending new elements at
        // the end of the vector
        for (int i = 1; i <= n; i++)
            v.add(i);

        // Printing elements
        System.out.println(v);

        // Remove element at index 3
        v.remove(3);

        // Displaying the vector
        // after deletion
        System.out.println(v);

        // iterating over vector elements
        // using for loop
        for (int i = 0; i < v.size(); i++)

            // Printing elements one by one
            System.out.print(v.get(i) + " ");
    }
}

[1, 2, 3, 4, 5]
[1, 2, 3, 5]
1 2 3 5

// Java Program to Add Elements in Vector Class

// Importing required classes
import java.io.*;
import java.util.*;

// Main class
// AddElementsToVector
class GFG {

    // Main driver method
    public static void main(String[] arg)
    {

        // Case 1
        // Creating a default vector
        Vector v1 = new Vector();

        // Adding custom elements
        // using add() method
        v1.add(1);
        v1.add(2);
        v1.add("geeks");
        v1.add("forGeeks");
        v1.add(3);

        // Printing the vector elements to the console
        System.out.println("Vector v1 is " + v1);

        // Case 2
        // Creating generic vector
        Vector<Integer> v2 = new Vector<Integer>();

        // Adding custom elements
        // using add() method
        v2.add(1);
        v2.add(2);
        v2.add(3);

        // Printing the vector elements to the console
        System.out.println("Vector v2 is " + v2);
    }
}

// Java code to change the
// elements in vector class
import java.util.*; 

// Driver Class
public class UpdatingVector { 
      // Main Function
    public static void main(String args[]) 
    { 
        // Creating an empty Vector 
        Vector<Integer> vec_tor = new Vector<Integer>(); 

        // Use add() method to add elements in the vector 
        vec_tor.add(12); 
        vec_tor.add(23); 
        vec_tor.add(22); 
        vec_tor.add(10); 
        vec_tor.add(20); 

        // Displaying the Vector 
        System.out.println("Vector: " + vec_tor); 

        // Using set() method to replace 12 with 21 
        System.out.println("The Object that is replaced is: "
                        + vec_tor.set(0, 21)); 

        // Using set() method to replace 20 with 50 
        System.out.println("The Object that is replaced is: "
                        + vec_tor.set(4, 50)); 

        // Displaying the modified vector 
        System.out.println("The new Vector is:" + vec_tor); 
    } 
}

Vector: [12, 23, 22, 10, 20]
The Object that is replaced is: 12
The Object that is replaced is: 20
The new Vector is:[21, 23, 22, 10, 50]

// Java code illustrating the removal
// of elements from vector

import java.util.*;
import java.io.*;

class RemovingElementsFromVector {
  
    public static void main(String[] arg)
    {
        // Create default vector of capacity 10
        Vector v = new Vector();

        // Add elements using add() method
        v.add(1);
        v.add(2);
        v.add("Geeks");
        v.add("forGeeks");
        v.add(4);

        // Removing first occurrence element at 1
        v.remove(1);

        // Checking vector
        System.out.println("after removal: " + v);
    }
}

// Java program to iterate the elements
// in a Vector

import java.util.*;

public class IteratingVector {

    public static void main(String args[])
    {
          // create an instance of vector
        Vector<String> v = new Vector<>();

          // Add elements using add() method
        v.add("Geeks");
        v.add("Geeks");
        v.add(1, "For");

        // Using the Get method and the
        // for loop
        for (int i = 0; i < v.size(); i++) {

            System.out.print(v.get(i) + " ");
        }

        System.out.println();

        // Using the for each loop
        for (String str : v)
            System.out.print(str + " ");
    }
}

Geeks For Geeks 
Geeks For Geeks

import java.util.Vector;

public class VectorExample {
    public static void main(String[] args) {
        // Create a new vector
        Vector<Integer> v = new Vector<>(3, 2);

        // Add elements to the vector
        v.addElement(1);
        v.addElement(2);
        v.addElement(3);

        // Insert an element at index 1
        v.insertElementAt(0, 1);

        // Remove the element at index 2
        v.removeElementAt(2);

        // Print the elements of the vector
        for (int i : v) {
            System.out.println(i);
        }
    }
}

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