Javadatatype

Data type

Data types are divided into two groups:

• Primitive data types - includes byte, short, int, long, float, double, boolean and char
• Non-primitive data types - such as String, Arrays and Classes

Data Type	Size	Description
byte	1 byte	Stores whole numbers from -128 to 127
short	2 bytes	Stores whole numbers from -32,768 to 32,767
int	4 bytes	Stores whole numbers from -2,147,483,648 to 2,147,483,647
long	8 bytes	Stores whole numbers from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
float	4 bytes	Stores fractional numbers. Sufficient for storing 6 to 7 decimal digits
double	8 bytes	Stores fractional numbers. Sufficient for storing 15 decimal digits
boolean	1 bit	Stores true or false values
char	2 bytes	Stores a single character/letter or ASCII values

Java divides the operators into the following groups:

• Arithmetic operators
• Assignment operators
• Comparison operators
• Logical operators
• Bitwise operators

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Arithmetic Operators

Arithmetic operators are used to perform common mathematical operations.

Operator	Name	Description	Example
+	Addition	Adds together two values	x + y
-	Subtraction	Subtracts one value from another	x - y
*	Multiplication	Multiplies two values	x * y
/	Division	Divides one value by another	x / y
%	Modulus	Returns the division remainder	x % y
++	Increment	Increases the value of a variable by 1	++x
--	Decrement	Decreases the value of a variable by 1	--x

Java Assignment Operators

A list of all assignment operators:

Operator	Example	Same As
=	x = 5	x = 5
+=	x += 3	x = x + 3
-=	x -= 3	x = x - 3
*=	x *= 3	x = x * 3
/=	x /= 3	x = x / 3
%=	x %= 3	x = x % 3
&=	x &= 3	x = x & 3
|=	x |= 3	x = x | 3
^=	x ^= 3	x = x ^ 3
>>=	x >>= 3	x = x >> 3
<<=	x <<= 3	x = x << 3

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Java Comparison Operators

Comparison operators are used to compare two values:

Operator	Name	Example
==	Equal to	x == y
!=	Not equal	x != y
>	Greater than	x > y
<	Less than	x < y
>=	Greater than or equal to	x >= y
<=	Less than or equal to	x <= y

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Java Logical Operators

Logical operators are used to determine the logic between variables or values:

Operator	Name	Description	Example
&&	Logical and	Returns true if both statements are true	x < 5 &&  x < 10
||	Logical or	Returns true if one of the statements is true	x < 5 || x < 4
!	Logical not	Reverse the result, returns false if the result is true	!(x < 5 && x < 10)

• In Java, every application begins with a class name, and that class must match the filename.

Let's create our first Java file, called MyClass.java, which can be done in any text editor (like Notepad).

The file should contain a "Hello World" message, which is written with the following code:

MyClass.java

public class MyClass {

  public static void main(String[] args) {

    System.out.println("Hello World");

  }

}

Save the code in Notepad as "MyClass.java". Open Command Prompt (cmd.exe), navigate to the directory where you saved your file, and type "javac MyClass.java":

C:\Users\Your Name>javac MyClass.java

C:\Users\Your Name>java MyClass

The output should read:

Hello World

 

Q. Write a program in JAVA two add two numbers given by users?

import java.util.Scanner; // Import the Scanner class

class MyClass {

  public static void main(String[] args) {

    int x, y, sum;

    Scanner myObj = new Scanner(System.in); // Create a Scanner object

    System.out.println("Enter a number:");

    x = myObj.nextInt(); // Read user input

    System.out.println("Enter another number:");

    y = myObj.nextInt(); // Read user input

    sum = x + y;  // Calculate the sum of x + y

    System.out.println("Sum is: " + sum); // Print the sum

  }

}

Control Statement in java

1. If……else
2. For……loop
3. While….loop
4. Do……while
5. Switch….case
6. Break
7. Continue
8. Goto

The if Statement

Use the if statement to specify a block of Java code to be executed if a condition is true.

if (condition) {

  // block of code to be executed if the condition is true

} else {

  // block of code to be executed if the condition is false

}

Example

int x = 20;

int y = 18;

if (x > y) {

  System.out.println("x is greater than y");

}