Using arrays in Java

JavaArrays.java

package com.diycomputerscience;

/**
 * This example explains how to create and use single and 
 * multidimensional arrays
 */

public class JavaArrays {

  public static void main(String args[]) {
    
    // create an array of primitives - 10 integers
    //Since an array is an object we have to instantiate
    //it with the new keyword
    int iArr[] = new int[10];
    
    // iterating across the array using a traditional for loop
    // notice how we get the length of the array
    for (int i = 0; i < iArr.length; i++) {
      // Assign a value to the i th location of the array
      iArr[i] = i * 100;
    }
    printArray(iArr);

    // create an array of floats
    // Here we create and populate the array at the same time
    float[] fArr = { 1.2f, 3.4f, 4.5f, 5.6f };    
    printArray(fArr);

    // Let's create an array of String objects
    // When creating an array of objects, we need to instantiate the array
    // object as well as the Objects which will be held in the array
    // We first create an array capable of holding 10 Strings
    String stringArr[] = new String[10];
    
    // Now let us create the Strings to put in the array
    for (int i = 0; i < 10; i++) {
      //notice that we had to instantiate the array object and 
      //each String object which we put into the array as well.
      stringArr[i] = new String(String.valueOf(i));
    }    
    printArray(stringArr);

    // Now let's create multidimensional arrays
    int iMultiDim[][] = new int[3][3];
    for (int d1 = 0; d1 < 3; d1++) {
      for (int d2 = 0; d2 < 3; d2++) {
        iMultiDim[d1][d2] = d1 * d2;
      }
    }
    printArray(iMultiDim);
  }

  private static void printArray(int array[]) {
    // printing array of integers
    // Here we will use the enhanced for loop
    for (int i : array) {
      System.out.print(i + " ");
    }
    System.out.println("");
  }

  private static void printArray(float array[]) {
    // printing array of floats
    for (float f : array) {
      System.out.print(f + " ");
    }
    System.out.println("");
  }

  private static void printArray(Object array[]) {
    // printing array of Objects
    for (Object f : array) {
      System.out.print(f + " ");
    }
    System.out.println("");
  }

  private static void printArray(int mDimArray[][]) {
    for (int i = 0; i < mDimArray.length; i++) {
      for (int j = 0; j < mDimArray[i].length; j++) {
        System.out.print(mDimArray[i][j]);
      }
      System.out.println("");
    }
  }
}