Monday, March 23, 2009
Assignment Operator In JAVA
variable_name = expression;
where,
expression is an arthmetic expression built using constants, variables and binary operators.
variable_name is the name of the variable to which the expression should be assigned.
For Example
a = 3;
x = 1*3;
num - x+8;
num1 = (4*a)+(21-a)
Note
It is also possible to assgn single value to multiple variables as shown below.
i = j = k = 10;
which will assgn the value 10 to the variables i, j and k.
Binary Operators In JAVA
Operator | Operation | Example |
+ | Addition | 2+3 is 5 |
- | Subtraction | 8-2 is 6 |
* | Multiplication | 2*5 is 10 |
/ | Division | 8/8 is 1 |
% | Modulo | 15%2 is 1 |
Example Program
class binaryoperatorexample
{
public static void main(String args[])
{
int a=10,b=5,c,d,e,f,g;
c=a+b;
d=a-b;
e=a*b;
f=a/b;
g=a%b;
System.out.println("Addition:"+c);
System.out.println("Subtraction:"+d);
System.out.println("Multiplication:"+e);
System.out.println("Division:"+f);
System.out.println("Modulo:"+g);
}
}
Please make sure to include all the necessary header files before compiling the program. The output of the program will be as below.
Addition: 15
Subtraction: 5
Multiplication: 50
Division: 2
Modulo: 0
Wednesday, March 18, 2009
What Is A Variable?
Every variable is identified by a variable name. The following points should be kept in mind when deciding the variable name.
- The variable name must start with an alphabet and can contain only alphabets , numbers,underscores and $ sign.
- It cannot have a blank spaces.
- Java keywords should not be used as variable names.
- Java is a case sensitive so a variable in uppercase is diffrent from the variable in lowercase.
What Is A Constant?
For example,
- -23 is a byte constant.
- 3213 is an integer constant.
- 13.654 is a float constant.
- true is a Boolean constant.
Integer constant can also be represented in octal and hexadecimal forms. An octal number should begin with the digit 0 and can contain the digits 0 to 7. A hexadecimal must start with the character sequence 0x and can contain the digits 0 to 9 and the alphabets A,B,C,D,E and F.
Data Types In Java
Data type in java can be of 8 basic type and these data types are called as primitive data types. The Following table contains the primitive data types.
Data Type | Size | Description |
Boolean | 1 Bit | Can be either true or false |
Char | 16 Bits | Can be single character enclosed with single ‘. |
Byte | 8 Bits | Integers between -128 to 12 |
Short | 16 Bits | Integers between -32768 to 32767 |
Int | 32 Bits | Integers between -2147483648 to 2147483647 |
Long | 64 Bits | Integers between -9223372036854775808 to 9223372036854775807 |
Float | 32 Bits | Single precision numbers in the range 3.4e-38 to 3.4e38 |
Double | 64 Bits | Double precision number in the range from 1.7e-308 to 1.7e308 |
Thursday, March 12, 2009
Java Developers Kit
- The java compiler javac.exe to convert java programs into bytecode.
- The java interpreter java.exe translates bytecode into program action to be executed by JVM.
- The Java debugger jdb.exe to debug the programs.
- The Java disassembler javap.exe to display certain specific interfaces.
- The Java header file generator javah.exe.
- The Java documentation javadoc.exe.
- AppletViewer.
what is an array?
For example, if the num is an integer array of size 5, these numbers would be referred as num[0], num[1],... num[4] where the number 0,1,2,3,4 are called the subscripts.
Important Rules In Array
- The Subscripts of an array always begins with 0.
- It is an integer.
- It cannot be a negative number.
- The subscripts should be enclosed with [].