Check Value is Integer or Not in Java using loop

Check value is integer or not in java using loop. In this article, you will learn how to check value is integer or not in java using while and for loop.

Examples

You should have knowledge of the following topics in java programming to understand these programs:

• Java Strings
• Java java.util.Scanner package
• Java main() method
• Java for loop statement
• Java while loop statement
• Java if-else condition statement
• Java break keyword
• Java System.out.println() function

Check Value is Integer or Not in Java using While loop

// Check Value is Integer or Not in Java using While loop
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);

        String random_number;
        int f = 0, i = 0;

        System.out.print("Enter the number to check itself: ");
        random_number = in.nextLine();

        while (random_number.charAt(i) != '\0' && i < (random_number.length() - 1)) {
            if (random_number.charAt(i) == '.') {
                f = 1;
                break;
            }
            i++;
        }

        if (f == 1)
            System.out.println("\n" + random_number + " is a floating-point number.");
        else
            System.out.println("\n" + random_number + " is an integer number.");
    }
}

Run Program

Output

Check Value is Integer or Not in Java using For loop

// Check Value is Integer or Not in Java using For loop
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);

        String random_number;
        int f = 0;

        System.out.print("Enter the number to check itself: ");
        random_number = in.nextLine();

        for (int i = 0; random_number.charAt(i) != '\0' && i < (random_number.length() - 1); i++) {
            if (random_number.charAt(i) == '.') {
                f = 1;
                break;
            }
        }

        if (f == 1)
            System.out.println("\n" + random_number + " is a floating-point number.");
        else
            System.out.println("\n" + random_number + " is an integer number.");
    }
}

Run Program

Output

Explanation

In this program, we have taken input 21.25 from the user and parsed this input as a string.

Meanwhile using for loop or while loop on this string we find the . symbol to verify It's an integer or floating-point number.