THINKING IN OBJECTS - Introduction to Java Programming - page 398

There is no limit to the precision of a BigDecimal object. The divide method may throw
an ArithmeticException if the result cannot be terminated. However, you can use
the overloaded divide(BigDecimal d, int scale, int roundingMode) method to
specify a scale and a rounding mode to avoid this exception, where scale is the maxi-
mum number of digits after the decimal point. For example, the following code creates two
BigDecimal objects and performs division with scale 20 and rounding mode
BigDecimal.ROUND_UP .

BigDecimal a = new BigDecimal( 1.0 );
BigDecimal b = new BigDecimal( 3 );
BigDecimal c = a.divide(b, 20 , BigDecimal.ROUND_UP);
System.out.println(c);

The output is 0.33333333333333333334 .
Note that the factorial of an integer can be very large. Listing 10.11 gives a method that can
return the factorial of any integer.

L ISTING 10.11 LargeFactorial.java
1 import java.math.*;
2
3 public class LargeFactorial {
4 public static void main(String[] args) {
5 System.out.println( "50! is \n" + factorial( 50 ));
6 }
7
8 public static BigInteger factorial( long n) {

9
10

BigInteger result = BigInteger.ONE;

constant

for ( int i = 1 ; i <= n; i++)

11
12
13

result = result.multiply( new BigInteger(i + "" )); multiply

return result;

14 }
15 }

50! is
30414093201713378043612608166064768844377641568960512000000000000

BigInteger.ONE (line 9) is a constant defined in the BigInteger class. BigInteger.ONE is
the same as new BigInteger("1") .
A new result is obtained by invoking the multiply method (line 11).

10.21 What is the output of the following code?

✓ ✓

Check

Point

public class Test {
public static void main(String[] args) {
java.math.BigInteger x = new java.math.BigInteger( "3" );
java.math.BigInteger y = new java.math.BigInteger( "7" );
x.add(y);
System.out.println(x);

}

}