Java中BigDecimal类的简单用法

/*The results of this constructor can be somewhat unpredictable. One might assume that 
new BigDecimal(.1) is exactly equal to .1, but it is actually equal 
to .1000000000000000055511151231257827021181583404541015625. This is so because .1 
cannot be represented exactly as a double (or, for that matter, as a binary fraction 
of any finite length). Thus, the long value that is being passed in to the constructor 
is not exactly equal to .1, appearances nonwithstanding.
The (String) constructor, on the other hand, is perfectly predictable: new BigDecimal
(".1") is exactly equal to .1, as one would expect. Therefore, it is generally 
recommended that the (String) constructor be used in preference to this one.*/

import java.math.*;
public class TestBigDecimal {
  public static void main(String args[]){
    BigDecimal bd = new BigDecimal("10.123");
    BigDecimal bd1 = new BigDecimal(10.123);
    System.out.println(bd +"/n"+ bd1);
  }
}

import java.math.*;
public class Libai {
  public static void main(String args[]){
    BigDecimal volumn = new BigDecimal("0");
    for (int i=0; i<5; i++){      
      volumn = volumn.add(new BigDecimal("1"));
      volumn = volumn.divide(new BigDecimal("2"));
    }
    System.out.print(volumn);
  }
}