Check Number Data Type in Java with Example

Learn how to Check Number Data Type in Java using range validation. In this program, we check which Java data type can store a given number. The program compares the input value against the ranges of byte, short, int, and long and displays all compatible data types.

Code Explanation (Step-by-Step)

  • Create a Scanner object reads the number entered through the keyboard.
  • nextLong() method is used to read a number of type long from the user, and the entered value is stored in the long variable m.
  • Check the byte range: If the number is between -128 and 127, it can be stored in the byte data type.
  • Check the short range: If the number is between -32,768 and 32,767, it can be stored in the short data type.
  • Check the int range: If the number is between -2,147,483,648 and 2,147,483,647, it can be stored in the int data type.
  • Check the long range: If the number is between -9,223,372,036,854,775,808L and 9,223,372,036,854,775,807L, it can be stored in the long data type .
  • Use try-catch: If the user enters text, a decimal number, or a value outside the long range, the catch block displays an error message.
				
					import java.util.Scanner;

public class TestData {

    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);

        System.out.print("Enter value: ");

        try {
            long m = sc.nextLong();

            if (m >= -128 && m <= 127) {
                System.out.println("byte");
            }

            if (m >= -32768 && m <= 32767) {
                System.out.println("short");
            }

            if (m >= -2147483648L && m <= 2147483647L) {
                System.out.println("int");
            }
            
            if (m >= -9223372036854775808L && m <= 9223372036854775807L) {
				System.out.println("long");
			}

        } catch (Exception e) {
            System.out.println("Invalid value");
        }

        sc.close();
    }
}

Input :- enter value :2147483647
Output :-
int
long

Advantages of Using Range Validation

Identifies the Appropriate Data Type
•  Range validation helps determine whether a number can be stored in a byte, short, int, or long data type based on its value.
Prevents Data Overflow
•  By checking the valid range before storing a value, the program avoids overflow and ensures accurate data storage.
Useful for Input Validation
•  It helps verify whether user-entered data is valid before performing further processing.
Reduces Runtime Errors
•  Checking the range beforehand prevents errors that may occur when assigning a value to a smaller data type.
Supports Efficient Memory Usage
•  Selecting the smallest suitable data type can help optimize memory consumption in applications.
Useful in Real-Time Applications
•  Range checks are commonly used in form validation, banking systems, data processing applications, and user input verification.

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