CODEWITHSUNDEEP
javabigdecimal
user1750751
user1750751

Reputation: 275

Why BigDecimal constructor instance with differents values?

I don't know why this happens:

float flo = 196.7f;
BigDecimal bd = new BigDecimal(flo);
System.out.println(bd); //print 196.6999969482421875

BigDecimal bd2 = new BigDecimal(Float.toString(flo));
System.out.println(bd2); //print 196.7

Upvotes: 1

Views: 50

Answers (1)

Codebender
Codebender

Reputation: 14438

Both your questions are clearly stated in the Javadoc.

  1. The results of this constructor can be somewhat unpredictable. One might assume that writing new BigDecimal(0.1) in Java creates a BigDecimal which is exactly equal to 0.1 (an unscaled value of 1, with a scale of 1), but it is actually equal to 0.1000000000000000055511151231257827021181583404541015625. This is because 0.1 cannot be represented exactly as a double (or, for that matter, as a binary fraction of any finite length). Thus, the value that is being passed in to the constructor is not exactly equal to 0.1, appearances notwithstanding.
  2. The String constructor, on the other hand, is perfectly predictable: writing new BigDecimal("0.1") creates a BigDecimal which is exactly equal to 0.1, as one would expect. Therefore, it is generally recommended that the String constructor be used in preference to this one.

Upvotes: 1

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