Lecture21Pass.java

import java.util.Scanner;
/**  
 * Lecture 21 
 * calling methods
 * pass arguments by value
 * 
 * @author PMCampbell
 * @version 2020-12-01
 */
public class Lecture21PassReference {
   
     public static void main(String[] args) {  
       double[] z = new double[] { 1.0, 2.0};
       double[] q = new double[] { 1.0, 3.0, 4.0 };                
       printArray(z);
       foo(q , z);
       printArray(z);
       
     }
     /**
      * fake method to illustrate
      * that an array as an argument is a pointer
      * 
      * we cannot change the pointer itself  
      * but we can change the content of the array
      */
     public static void foo(double x[], double y[]) {
       y[0]= 5;
     }
  /**
   * display contents of an array with {}
   * from lab 19
   * 
   * @param array array to be printed
   */
  public static void printArray(int array[]) {
    System.out.print("{ ");
    for(int i=0;i <array.length; i++) {
      if (i == array.length-1) {
        System.out.print(array[i]);
      }else { System.out.print(array[i] + ","); }
    }
    System.out.println(" }");
  }

}