Java Basics:Data Types

 

Data Types in Java

Data types specify the different sizes and values that can be stored in the variable. There are two types of data types in Java:

1. Primitive data types: The primitive data types include boolean, char, byte, short, int, long, float and double.
2. Non-primitive data types: The non-primitive data types include Classes,Interfaces,Arrays.

1) Primitive data types

In Java, we have eight primitive data types: boolean, char, byte, short, int, long, float and double. Java developers included these data types to maintain the portability of java as the size of these primitive data types do not change from one operating system to another.

byte, short, int and long data types are used for storing whole numbers.

float and double are used for fractional numbers.

char is used for storing characters(letters).

boolean data type is used for variables that holds either true or false.

byte:

This can hold whole number between -128 and 127. Mostly used to save memory and when you are certain that the numbers would be in the limit specified by byte data type.
Default size of this data type: 1 byte.
Default value: 0
Example:

class JavaExample {
    public static void main(String[] args) {
    	
    	byte num;
    	
    	num = 113;
    	System.out.println(num);
    }
}

Output:

113

Try the same program by assigning value assigning 150 value to variable num, you would get type mismatch error because the value 150 is out of the range of byte data type. The range of byte as I mentioned above is -128 to 127.

short:

This is greater than byte in terms of size and less than integer. Its range is -32,768 to 32767.
Default size of this data type: 2 byte

short num = 45678;

int: Used when short is not large enough to hold the number, it has a wider range: -2,147,483,648 to 2,147,483,647
Default size: 4 byte
Default value: 0
Example:

class JavaExample {
    public static void main(String[] args) {
    	
    	short num;
    	
    	num = 150;
    	System.out.println(num);
    }
}

Output:

150

The byte data type couldn’t hold the value 150 but a short data type can because it has a wider range.

long:

Used when int is not large enough to hold the value, it has wider range than int data type, ranging from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807.
size: 8 bytes
Default value: 0
Example:

class JavaExample {
    public static void main(String[] args) {
    	
    	long num = -12332252626L;
    	System.out.println(num);
    }
}

Output:

-12332252626

double: Sufficient for holding 15 decimal digits
size: 8 bytes
Example:

class JavaExample {
    public static void main(String[] args) {
    	
    	double num = -42937737.9d;
    	System.out.println(num);
    }
}

Output:

-4.29377379E7

float: Sufficient for holding 6 to 7 decimal digits
size: 4 bytes

class JavaExample {
    public static void main(String[] args) {
    	
    	float num = 19.98f;
    	System.out.println(num);
    }
}

Output:

19.98

boolean: holds either true of false.

class JavaExample {
    public static void main(String[] args) {
    	
    	boolean b = false;
    	System.out.println(b);
    }
}

Output:

false

char: holds characters.
size: 2 bytes

class JavaExample {
    public static void main(String[] args) {
    	
    	char ch = 'Z';
    	System.out.println(ch);
    }
}

Output:

Z

Literals in Java

A literal is a fixed value that we assign to a variable in a Program.

int num=10;

Here value 10 is a Integer literal.

char ch = 'A';

Here A is a char literal

Integer Literal

Integer literals are assigned to the variables of data type byte, short, int and long.

byte b = 100;
short s = 200;
int num = 13313131;
long l = 928389283L;

Float Literals

Used for data type float and double.

double num1 = 22.4;
float num2 = 22.4f;

Note: Always suffix float value with the “f” else compiler will consider it as double.

Char and String Literal

Used for char and String type.

char ch = 'Z';
String str = "BeginnersBook";

Java Program to Add two Numbers

Here we will see two programs to add two numbers, In the first program we specify the value of both the numbers in the program itself. The second programs takes both the numbers (entered by user) and prints the sum.

First Example: Sum of two numbers

public class AddTwoNumbers {

   public static void main(String[] args) {
        
      int num1 = 5, num2 = 15, sum;
      sum = num1 + num2;

      System.out.println("Sum of these numbers: "+sum);
   }
}

Output:

Sum of these numbers: 20

Second Example: Sum of two numbers using Scanner

The scanner allows us to capture the user input so that we can get the values of both the numbers from user. The program then calculates the sum and displays it.

import java.util.Scanner;
public class AddTwoNumbers2 {

    public static void main(String[] args) {
        
        int num1, num2, sum;
        Scanner sc = new Scanner(System.in);
        System.out.println("Enter First Number: ");
        num1 = sc.nextInt();
        
        System.out.println("Enter Second Number: ");
        num2 = sc.nextInt();
        
        sc.close();
        sum = num1 + num2;
        System.out.println("Sum of these numbers: "+sum);
    }
}

Output:

Enter First Number: 
121
Enter Second Number: 
19
Sum of these numbers: 140

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