Large Integer Computing - Introduction to Cryptography with Java Applets - page 60

E XAMPLE .

An example of how this method may be called follows:

BigInteger bigBoy=new BigInteger( “ 255 ” );
System.out.println(bigBoy.toString());

However, it is often not necessary to convert BigIntegers to Strings before printing them,
for we can use implicit calls to a toString() method by concatenating a BigInteger to a String
using the “ + ” concatenation operator:

BigInteger bigBoy=new BigInteger( “ 255 ” );
System.out.println( “ This # is: “ +bigBoy);
The BigInteger will be displayed in base 10.

• public byte[] toByteArray()

This method converts a BigInteger into a raw array of bytes. In effect, it returns the
two ' s - complement binary representation of this number in the array, which is big-endian
(that is, the most significant byte is in the [0] position). The array contains the minimum num-
ber of bytes required to represent the number. For example, suppose b is a BigInteger hav-
ing the value 987654321=111010110111100110100010110001 base 2 . (You may wish to verify
that this is actually the base 2 representation of 987654321.) Then we make the following
call:

byte[] a=b.toByteArray();

This will produce a byteArray of 4 bytes, assign it to , and the most significant digits

a

of the BigInteger will be first. That is,

b

a[0]=00111010,

a[1]=11011110,
a[2]=01101000, and

a[3]=10110001.

This representation is compatible with the (byte[]) constructor.

• public int intValue()

This method converts this number to an int.

• public long longValue()

This method converts this number to a long.

• public float floatValue()

number to a float. It is similar to the double-to-float narrow-
ing primitive conversion defined in The Java Language Specification: If the number has
too great a magnitude to represent as a float, it will be converted to infinity or negative
infinity as appropriate.

This method converts this