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Wednesday, October 5, 2016

Basic Data Types (Numbers)-Tutorial

Numbers in Java

Remembering the Java Number data types again. There are six Java number data types. Four of which are Integers, two are floating point numbers
Let us discover the properties of each and every data type and what can we do with them!

Some Common Properties of Integer Numbers


All the 4 data types mentioned under Integer Numbers are signed, i.e. all the data types can store both positive and negative values in them.
All of them have a particular width assigned, that it can utilize in memory.
Based on the size assigned, each data type can store a particular range of data in memory.

byte


Smallest in term of width assigned to it, which is : 8 bit
Storage limit: -128 to 127
Keyword: byte
·       Usage : Useful while handling file or network data or raw file formats
Example:
public static void main(String[] args)
{
   byte b = 76; // This is correct as byte stores from range -128 to 127
   byte c = -23;// This is correct as byte stores from range -128 to 127
   byte d = 129; // This is not correct as byte stores from range -128 to 127
   byte e = -456;// This is not correct as byte stores from range -128 to 127
}

short


short is assigned a width of 16 bits
·       Storage limit: -32,768  to 32,767
·       Keyword: short
·      Probably the least used data type in Java Numbers
Example: 
public static void main(String[] args)
{
 short a = 30000; // This is correct as short stores from range -128 to 127
 short b = -24587; // This is correct as short stores from range -128 to 127
 short c = 32890; // this is not correct as short stores from range -128 to 127
 short d = -87547; // This is not correct as short stores from range -128 to 127
}

int


short is assigned a width of 32 bits
·      Storage limit: –2,147,483,648 to 2,147,483,647.
·      Keyword: int
·      most used data type in Java Numbers
·      Whenever any calculation is made on short or byte, first it is converted to int before any operation. This is Type Promotion. Thus, we can say that choosing int in a program is a wise decision.
·       Example:
public static void main(String[] args)
{
 int a = 30000;
 int b = -24587
 int c = 464758976076654; // This is not correct as it is larger than the int range
 int d = -45743642532626437; // This is not correct as it is smaller than the int range
}

long


 short is assigned a width of 64 bits
·        Storage limit: -18446744073709551616 to 18446744073709551615
·        Keyword: long
·        Need to use suffix L while assigning a value to the variable. Because, default data type for numbers is int.
·        Use: When int is not enough to store a data, in those cases, long is used as data types.
Example:
public static void main(String[] args)
{
 int a = 21474836487686574L; // error, because, it is out of the range for int
 long b = 21474836487686574L;
}

Some Common Properties of Floating Point Numbers


Both float and double are signed data types, i.e. all the data types can store both positive and negative values in them.
·       All of them have a particular width assigned, that it can utilize in memory.
·       Based on the size assigned, each data type can store a particular range of data in memory.
·       Whenever there is a need to fractional or decimal numbers to use in the program, we use double or float.
·        Also called real numbers.

float

·       short is assigned a width of 32 bits
·      Storage limit: 1.4e–045 to 3.4e+038
·      Keyword: float
·      Need to use suffix f while assigning a value to the variable. Because, default data type for floating point numbers is double.
·      Use: When fraction or decimal must be used, precision is not that big, we use float.
Example:
public static void main(String[] args)
{
 float d = -876.9896596f;
}

double

·        short is assigned a width of 64 bits
·        Storage limit: 4.9e–324 to 1.8e+308
·        Keyword: double
·        Use: When need to maintain accuracy in big calculation, we should use double.
·        double is faster than float.
Example:
public static void main(String[] args)
{
 double d = -876.9896596f;
}

In a Nutshell:


ta Types
Width
Range
Keyword
Suffix
byte
8
-128 to 127
byte
   -
short
16
-32,768  to 32,767
short
   -
int
32
–2,147,483,648 to 2,147,483,647
int
   -
long
64
-18446744073709551616 to 18446744073709551615
long
   L
float
32
1.4e–045 to 3.4e+038
float
   f
double
64
4.9e–324 to 1.8e+308
double
   -

 Some widely used Java Number Methods

 Method
Description
Result Data type
Example
compareTo

Compares one variable to another variable of same data type
true or false
Double b = 0.09;
b.compareTo(34.87);

returns false
equals
Compares one variable to another. Returns true if both are same, else, return false.
true or false
Integer i = 3;
System.out.println(i.equals("Test"));
System.out.println(i.equals(3));

Prints :
False
true
toString
Convert the variable in signed decimal representation and then returned as a String exactly as the parameter provided to it.
String
Long l = 34L;
System.out.println(l.toString());

Prints:

34
valueOf(int i)
Returns Integer instance of the parameter provided
Integer
System.out.println(Integer.valueOf(5));

Prints: 5
valueOf(String s)
Returns Integer instance of the String provided as a parameter. If the String is not in right format, it will throw exception.
Integer
System.out.println(Integer.valueOf("8"));

Prints: 8
Value
For example :
intValue() Method 
Convert the input to int (by casting).
Same for floatValue(), doubleValue() etc.
mentioned in the method name
Double b = 1.09;
System.out.println(b.intValue());

Prints: 1
parseInt parseFloat parseDouble parseLong

Takes input as a String and convert the string to the data type required. If not the proper format is provided, it throws error
mentioned in the method name
System.out.println(Float.parseFloat("56.98f"));
System.out.println(Integer.parseInt("200"));
Prints:
56.98
200
isNan
Check if the parameter is a number or not. Can be applied only on float and double
true or false
Double d = 5.0;
System.out.println(d.isNaN());
Float e = 234.0f;
System.out.println(e.isNaN());
Prints:
false
false
Math.abs
Returns the absolute value of the variable provided as parameter
All Java Number data types
Double d = -5.34465768;
System.out.println(Math.abs(d));
Float e = -5.344f;
System.out.println(Math.abs(e));
             
Integer i = -5;
System.out.println(Math.abs(i));

Prints:
5.34465768
5.344
5
Math.cos
Calculates the cosine value of the angle (provided as parameter) trigonometrically.
Double
(if the argument is 0 or NaN, the result is NaN)
Double d = -5.34465768;
System.out.println(Math.cos(d));

Prints:
0.5909764119042038
Math.sin
Calculates the sine value of the angle (provided as parameter) trigonometrically.
Double
(if the argument is 0 or NaN, the result is NaN)
Double d = -5.34465768;
System.out.println(Math.sin(d));

Prints:
0.8066888375159488
Math.tan
Calculates the tangent value of the angle (provided as parameter) trigonometrically.
Double
(if the argument is 0 or NaN, the result is NaN)
Double d = -5.34465768;
System.out.println(Math.tan(d));

Prints:
1.3650102123648067
Math.ceil
Calculates the smallest (closest to negative infinity) floating-point value that is greater than or equal to the argument and is equal to a mathematical integer
Double (If the argument is NaN or an infinity or positive zero or negative zero, then the result is the same as the argument)
Double d = -5.34465768;
System.out.println(Math.ceil(d));
Integer i = 6;
System.out.println(Math.ceil(i));

Prints:
-5.0
6.0
Math.cbrt
Calculates cube root of the
Double
Integer i = 6;
System.out.println(Math.cbrt(i));

Prints:
1.8171205928321397
Math.sqrt

Calculates cube root of the
Double
Integer i = 6;
System.out.println(Math.sqrt(i));

Prints:
2.449489742783178
Math.exp

Calculate the value e^(parameter), where e is the base of the natural logarithms
Double(If the argument is NaN, the result is NaN.)
Integer i = 6;
System.out.println(Math.exp(i));

Prints:
403.4287934927351
Math.floor
Calculates the largest (closest to positive infinity) floating-point value that less than or equal to the argument and is equal to a mathematical integer.

Double
Double i = 67.986;
System.out.println(Math.floor(i));

Prints:
67.0
Math.max
Compares two parameters of same data types and returns the largest one. Can be applied to only long, float, double or int.
Long/ int/ float/double
Double i = 67.986;
System.out.println(Math.max(23, 567));
Prints:
567
Math.min
Compares two parameters of same data types and returns the smallest one. Can be applied to only long, float, double or int.
Long/ int/ float/double
Double i = 67.986;
System.out.println(Math.min(23, 567));
Prints:
23
Math.pow
Calculates the value a^b where a is the first parameter and b is the second.
Double
Double i = 67.986;
Double a = 2.0;
System.out.println(Math.pow(a, i));

Prints:
2.9229762406033716E20
Math.random

Returns a pseudorandom double greater than or equal to 0.0 and less than 1.0.

Double
System.out.println(Math.random());

Prints:
0.050148991557008915
Math.toDegrees
Calculates the measurement of the angle angrad in degrees.

Double
Double i = 67.986; 
System.out.println(Math.toDegrees(i));

Prints:
3895.3108659764152
Math.toRadians
Calculates the measurement of the angle in radians
Double
Double i = 67.986; 
System.out.println(Math.toRadians(i));

Prints:
1.186579545260865



  

 Basic Data Types (Characters)

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