Data types: -
A data type represents the type
of data stored in variable.
Integer data types: -
These
data types represent integer numbers
Data
type Memory size min and max value
1. byte 1 Byte - 128 to +127
2.
short 2
Bytes
- 32768 to +32767
3.
int 4
Bytes
- 21474836 to +2147483647
4.
long 8 Bytes -9223372036854775808 to
+9223372036854775807
Float data types: - Float means floating
point numbers. Float data type represent numbers with decimal points.
Ex: -
1.5, 3.14159,-2.2, 100.0 etc….
Float means single precision floating
point number. Double means double precision floating point number. Precision
means accuracy.
Data
type Memory
size min
and max value
1)
float 4 bytes 1.4e-45 to
+3.4e38.
2) double 8 bytes 4.1e-324
to+1.8e308.
e means into 10 powers. (x 10power).
Character data type: -
Data
type Memories
size min
and max valve
char 2 bytes 0 to
65535
This data type represents a single
character. In C or CPP languages using
only one byte in a char.
Ex:
- char ch = ‘x’;
Single character literal write inside the ‘
’(single code).
write string in the double codes (“ ”).
A
string represent group of characters.
EX:
-
String name=“narendar reddy”;
ASCII: -
American Standard Code for Information Interchange.
Boolean
data types: - These data types represent only 2 values either a true or false.
EX:
- boolean response=true;
Operators:
- An operator is a symbol that performs on an operation.
EX:
-
If
an operator acts on a single variable, it is called unary operator.
If
an operator acts on a 2 variables, it is called binary operator.
If
an operator acts on a 3 variables, it is called ternary operator.
Operators
in java: -
1) Arithmetic
operators: - + , - , * , / , %
These
operators perform basic arithmetic calculations.
EX: -
If a=5, b=5;
Operator
a + b
Operands
2)
Unary operators: - - , ++ , --
These operators act upon a single
operand.
àUnary
minus ( - ):- This operator negates the value of a variable.
EX:-
int
x=5;
System.out.println(-x); o/p:- -5
System.out.println(-(-x)); o/p:-
5
Increment
(++): - This operator increases the value of a variable by ‘1‘.
EX:
- public class UnaryOperator {
public static void main(String args[])
{
int a=10;
System.out.println(" a
is"+a); // a=10
++a;
System.out.println(" a is"+a); //a=11
}
}
Writing
++ before a variable is called pre – incrementation
Writing
++ after a variable is called post – incrementation
àWhat
is the value of the following expression? Given a=7? ++a * a++?
A)
A) 49 B) 64 C) 72 D) none of these
Decrement
(--): - This operator decreases the value of a variable by ‘1‘.
EX: -
int x=1;
--x; O/P: 0
x--; O/P:
-1
Writing
-- before a variable is called pre – decrementation
Writing
-- after a variable is called post – decrementation
3)
Assignment operators: -
= , += , -= , *= , /= , %=
a) This operator is used to store a
value in to a variable.
EX:
- int x=5;
b) It is used to store the value of
a variable in to another variable.
EX:
- int x=y;
c) It is used to store the value of
an expression in to a variable.
EX:
- int x = y + z - 4;
Expressions mean combination of a
variables & values.
Note:
- We can not write more than 1 variable at the left side of
assignment.
EX: - x
+ y = 15; // invalid
4)
Relational operator: - < , > , <= , >= , == , !=
These operators are useful to
compare to quantities. They are used in construction of condition.
EX:
-
if(a>b)
if(a<=b)
5)
Logical operators: - &&(and) , | |(or) , !(not)
These operators are useful to create
compound condition. The compound condition is condition of several simple
conditions.
EX:
-
If(a>b||b>c||c>d)-----;
Any one thing is true this will be
executed;
If(x==10&&y!=10)----;
Both are true this will be executed.
If(!(x==!))------;
If(!(x==1 && y==2))----;
6)
Boolean operators: - & , | , !
Boolean operators act upon Boolean
variables and they return Boolean result
boolean
a,b;
a=true;
b=false;
EX:
-
a & b à
false
a | b à true
a & a à
true boolean type results
b | b àfalse
! a à false
! b à true
7)
Bitwise operators: - ~ , & , | , ^ ,
<< , >> , >>>
These operators act up on individual
bits binary digits, (0&1) of numbers.
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