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Siva Nookala - 14 Apr 2016
The abstract class `Number` is the superclass of classes `BigDecimal, BigInteger, Byte, Double, Float, Integer, Long` and `Short`. Subclasses of `Number` must provide methods to convert the represented numeric value to `byte, double, float, int, long` and `short`.

Number Constructor :
ConstructorDescription
`Number()`Creates single Constructor.

Number Methods :
MethodDescription
`byte byteValue()` Returns the value of the specified number as a `byte`.
`abstract double doubleValue()` Returns the value of the specified number as a `double`.
`abstract float floatValue()`Returns the value of the specified number as a `float`.
`abstract int intValue()` Returns the value of the specified number as an `int`.
`abstract long longValue()` Returns the value of the specified number as a `long`.
`short shortValue()`Returns the value of the specified number as a `short`.

Number Test
`class NumberTest{    public static void main(String arg[])    {        Integer i = new Integer(123456);        Float f = new Float(789);        Double d = new Double(3456);        Long l = new Long(654321);                System.out.println("Integer i value is converted into Byte : " + i.byteValue());        System.out.println("Float f value is converted into Double : " + f.doubleValue()); // LINE A        System.out.println("Long l value is converted into Float : " + l.floatValue()); // LINE B        System.out.println("Integer i value is converted into Long : " + i.longValue()); // LINE C        System.out.println("Float f value is converted into Short : " + f.shortValue());        }}`
OUTPUT

Integer i value is converted into Byte : 64
Float f value is converted into Double : 789.0
Long l value is converted into Float : 654321.0
Integer i value is converted into Long : 123456
Float f value is converted into Short : 789

DESCRIPTION

In this program, we are converting an input required data type into specified data type.

THINGS TO TRY
• In `LINE A` replace `f` by `i` and see the result which converts `Integer` into `Double`.
• At `LINE B` replace `l` by `i` and see the result which converts `Integer` into `Float`.
• In `LINE C` replace `i` by `d` and see the result which converts `Double` into `Long`.

Number instance methods :
MethodDescription
`compareTo()`Compares this Number object to the argument.
`equals()`Determines whether this number object is equal to the argument.
`valueOf()`Returns an Integer object holding the value of the specified primitive.
`toString()`Returns a String object representing the value of specified int or Integer.
`parseInt()`This method is used to get the primitive data type of a certain String.
`abs()`Returns the absolute value of the argument.
`ceil()`Returns the smallest integer that is greater than or equal to the argument. Returned as a double.
`floor()`Returns the largest integer that is less than or equal to the argument. Returned as a double.
`rint()`Returns the integer that is closest in value to the argument. Returned as a double.
`round()`Returns the closest long or int, as indicated by the method's return type, to the argument.
`min()`Returns the smaller of the two arguments.
`max()`Returns the larger of the two arguments.
`exp()`Returns the base of the natural logarithms, e, to the power of the argument.
`log()`Returns the natural logarithm of the argument.
`pow()`Returns the value of the first argument raised to the power of the second argument.
`sqrt()`Returns the square root of the argument.
`sin()`Returns the sine of the specified double value.
`cos()`Returns the cosine of the specified double value.
`tan()`Returns the tangent of the specified double value.
`asin()`Returns the `arcsine` of the specified double value.
`acos()`Returns the `arccosine` of the specified double value.
`atan()`Returns the `arctangent` of the specified double value.
`atan2()`Converts rectangular coordinates `(x, y)` to polar coordinate `(r, theta)` and returns theta.
`toDegrees()`Converts the argument to degrees.
`toRadians()`Converts the argument to radians.
`toHexString()`Returns a string holding the value of specified primitive.
`toBinaryString()`Returns a string that contains the binary equivalent of specified primitive.
`toOctalString()`Returns a string that contains the octal equivalent of specified primitive.
`bitCount()`Returns the number of set bits of specified primitive.
`reverse()`Reverse the order of the bits in specified primitive and returns the result.
`rotateLeft(long num, int n)`Returns the result of rotating in specified primitive `num`left `n` positions.
`rotateRight(long num, int n)`Returns the result of rotating in specified primitive `num`right `n` positions.
`signum()`Returns -1 if specified primitive is negative, 0 if it is zero, and 1 if it is positive.

Number Method Test1
`class NumberMethodTest1{    public static void main(String arg[])    {        Integer a = 5;        Integer b = 6;        String c = "8";                    System.out.println("Compares two Intergers : " + a.compareTo(b));        System.out.println("Checks for equal : " + a.equals(b));        System.out.println("Converts to Float : " + Float.valueOf(b));        System.out.println("Converts to String : " + Integer.toString(a));        System.out.println("Converts String to Integer : " + Integer.parseInt(c));        }}`
OUTPUT

Compares two Intergers : -1
Checks for equal : false
Converts to Float : 6.0
Converts to String : 5
Converts String to Integer : 8

DESCRIPTION

In this program, `compareTo, equals, valueOf, toString` and `parseInt<cw>` methods are used.

THINGS TO TRY
• Give b value as 5 and check the output for `compareTo` and `equals`.

Subtract() method performs the subtraction of given two BigDecimal numbers.

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