Interview question

What are variables and data types in Java? Java में variables और data types क्या हैं?

Answer

Variables are named memory locations that store values. Data types define the type of data a variable can hold.

Data Type	Size	Range	Example
byte	1 byte	-128 to 127	byte b = 10;
short	2 bytes	-32,768 to 32,767	short s = 1000;
int	4 bytes	-2^31 to 2^31-1	int i = 100000;
long	8 bytes	-2^63 to 2^63-1	long l = 10000000000L;
float	4 bytes	Single precision	float f = 3.14f;
double	8 bytes	Double precision	double d = 3.14;
char	2 bytes	Unicode (0 to 65,535)	char c = 'A';
boolean	1 bit	true or false	boolean flag = true;

// Primitive Data Types
public class DataTypes {
    public static void main(String[] args) {
        // Numeric types
        byte age = 25;
        short distance = 5000;
        int salary = 50000;
        long population = 1000000000L;
        
        // Decimal types
        float price = 19.99f;
        double pi = 3.14159265;
        
        // Character type
        char gender = 'M';
        
        // Boolean type
        boolean isActive = true;
        
        // Reference Types (Non-primitive)
        String name = 'John';
        int[] numbers = {1, 2, 3, 4, 5};
    }
}

// Type Casting
int a = 10;
long b = (long) a;  // Implicit casting (widening)

double x = 10.5;
int y = (int) x;    // Explicit casting (narrowing)

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