// Zorah Fung, CSE 142
// Demo of using arrays

import java.util.*; // to use the Arrays utility class

public class ArraysDemo {
   public static void main(String[] args) {
      int[] a = new int[5]; // Creates an array of 5 elements. Initially filled with 0's.
      
      // Can use elements in arrays the same way we use variables
      a[2] = 42; // Modify element at index 2
      System.out.println(a[2]); // Access element at index 2
      
      // Similar syntax to variables. array[i] *is* a variable
      int x = 0; // declare integer variable
      int[] array = new int[10]; // declare array
      
      x = 2; // assign x to 2
      array[3] = 2; // assign element at index 3 to 2
      
      System.out.println(2 * x + 1); // use value of x in an expression
      System.out.println(2 * array[3] + 1); // use value of element at index 3 in an expession
      
      x = 2 * x; // reassign x to be twice as much
      array[3] = 2 * array[3]; // reassign element at index 3 to be twice as much.
      
      x++; // increment x
      array[3]++; // increment element at index 3
      
      
      // Use .length property of arrays to loop over an array
      for (int i = 0; i < a.length; i++) {
         a[i] = i;
      }
      
      // Must use Arrays.toString to print out the contents of an array
      System.out.println(Arrays.toString(a));
      
      int[] b = {0, 1, 2, 3, 4}; // Example of "quick initialization"
      System.out.println("a == b" + (a == b)); // Won't work
      System.out.println("a.equals(b)" + a.equals(b)); // Also won't work
      System.out.println(Arrays.equals(a, b)); // Must use Arrays class
      
      
      // Arrays of other types
      String[] groceries = {"goat cheese", "bananas", "pickles", "ham"};
      groceries[0] = "cheddar cheese";
      
      boolean[] booleanArray = new boolean[7]; // Initially all false;
      double[] doubleArray = new double[5]; // Initially all 0.0;
      
      // Can have array with ANY type of element. Example of Array of arrays
      // Anything before [] is the type of the element so "int[]" is the type
      // of element stored in this array. Each element is an integer array.
      int[][] arrayOfArrays = {{1, 2}, {3, 4, 5}, {6}, {7, 8, 9, 10}};
   }
}