diff options
Diffstat (limited to 'java.html.markdown')
| -rw-r--r-- | java.html.markdown | 25 |
1 files changed, 16 insertions, 9 deletions
diff --git a/java.html.markdown b/java.html.markdown index 1813f81c..84978ecc 100644 --- a/java.html.markdown +++ b/java.html.markdown @@ -128,7 +128,7 @@ public class LearnJava { // // BigInteger can be initialized using an array of bytes or a string. - BigInteger fooBigInteger = new BigDecimal(fooByteArray); + BigInteger fooBigInteger = new BigInteger(fooByteArray); // BigDecimal - Immutable, arbitrary-precision signed decimal number @@ -144,7 +144,12 @@ public class LearnJava { // or by initializing the unscaled value (BigInteger) and scale (int). BigDecimal fooBigDecimal = new BigDecimal(fooBigInteger, fooInt); - + + // Be wary of the constructor that takes a float or double as + // the inaccuracy of the float/double will be copied in BigDecimal. + // Prefer the String constructor when you need an exact value. + + BigDecimal tenCents = new BigDecimal("0.1"); // Strings @@ -207,8 +212,8 @@ public class LearnJava { System.out.println("1+2 = " + (i1 + i2)); // => 3 System.out.println("2-1 = " + (i2 - i1)); // => 1 System.out.println("2*1 = " + (i2 * i1)); // => 2 - System.out.println("1/2 = " + (i1 / i2)); // => 0 (0.5 truncated down) - System.out.println("1/2 = " + (i1 / (i2*1.0))); // => 0.5 + System.out.println("1/2 = " + (i1 / i2)); // => 0 (int/int returns an int) + System.out.println("1/2 = " + (i1 / (double)i2)); // => 0.5 // Modulo System.out.println("11%3 = "+(11 % 3)); // => 2 @@ -416,7 +421,7 @@ public class LearnJava { // easier way, by using something that is called Double Brace // Initialization. - private static final Set<String> COUNTRIES = HashSet<String>() {{ + private static final Set<String> COUNTRIES = new HashSet<String>() {{ add("DENMARK"); add("SWEDEN"); add("FINLAND"); @@ -701,10 +706,12 @@ public abstract class Mammal() // Enum Type // -// An enum type is a special data type that enables for a variable to be a set of predefined constants. The // variable must be equal to one of the values that have been predefined for it. -// Because they are constants, the names of an enum type's fields are in uppercase letters. -// In the Java programming language, you define an enum type by using the enum keyword. For example, you would -// specify a days-of-the-week enum type as: +// An enum type is a special data type that enables for a variable to be a set +// of predefined constants. The variable must be equal to one of the values that +// have been predefined for it. Because they are constants, the names of an enum +// type's fields are in uppercase letters. In the Java programming language, you +// define an enum type by using the enum keyword. For example, you would specify +// a days-of-the-week enum type as: public enum Day { SUNDAY, MONDAY, TUESDAY, WEDNESDAY, |