Mumbai University > Information Technology > Sem 3 > Object Oriented Programming Methodology

Marks: 5 M

Year: Dec 2013, May 2014, May 2015, Dec 2014

• The arraycopy( ) method can be used to copy quickly an array of any type from one place to another. This is much faster than the equivalent loop written out longhand in Java.
• Let’s take an example of two arrays being copied by the arraycopy( ) method. First, array named a is copied to array named b.

• Next, all of a’s elements are shifted down by one. Then, b is shifted up by one.

  class ACDemo 
  {
  static byte a[] = { 65, 66, 67, 68, 69, 70, 71, 72, 73, 74 };
  static byte b[] = { 77, 77, 77, 77, 77, 77, 77, 77, 77, 77 };
  public static void main(String args[])
  {
  System.out.println("a = " + new String(a));
  System.out.println("b = " + new String(b));
  System.arraycopy(a, 0, b, 0, a.length);
  System.out.println("a = " + new String(a));
  System.out.println("b = " + new String(b));
  System.arraycopy(a, 0, a, 1, a.length - 1);
  System.arraycopy(b, 1, b, 0, b.length - 1);
  System.out.println("a = " + new String(a));
  System.out.println("b = " + new String(b));
  }
  }
  

• As you can see from the following output, you can copy using the same source and destination in either direction:

a = ABCDEFGHIJ

b = MMMMMMMMMM

a = ABCDEFGHIJ

b = ABCDEFGHIJ

a = AABCDEFGHI

b = BCDEFGHIJJ