Java Program to Find Sum of First and Last Digit of a Number

1 Comment

Learn how to find sum of first and last digit of a number in Java using a simple while loop with example code and output.

Code Explanation (Step-by-Step)

  • Initialize a number (56789).
  • Copy the number into firstDigit int variable .
  • Use a while loop to divide the number by 10 until only one digit remains.
  • The remaining digit is the first digit.
  • Use the modulus operator (% 10) to get the last digit.
  • Add the first and last digits to store in sum variable.
  • Now print the sum value.
				
					public class SumFirstLastNumber {

    public static void main(String[] args) {

        int number = 56789;
        int firstDigit = number;

        while (firstDigit >= 10) {
            firstDigit = firstDigit / 10;
        }

        System.out.println("First digit number: " + firstDigit);

        int lastDigit = number % 10;
        System.out.println("Last digit number: " + lastDigit);

        int sum = firstDigit + lastDigit;

        System.out.println("Sum of first and last digit of a number: " + sum);
    }
}

Output :-
First digit number:  5
Last digit number: 9
Sum of first and last digit of a number:  14

Java 8 Program to Calculate First and Last Digit Sum

				
					public class FirstLastDigitSum {

    public static void main(String[] args) {

        int number = -56789;

        // Validate input
        if (number < 0) {
            System.out.println("Invalid input! Please enter a positive number.");
            return;
        }

        String num = String.valueOf(number);

        int firstDigit = Character.getNumericValue(num.charAt(0));
        int lastDigit = Character.getNumericValue(num.charAt(num.length() - 1));

        int sum = firstDigit + lastDigit;

        System.out.println("First Digit: " + firstDigit);
        System.out.println("Last Digit: " + lastDigit);
        System.out.println("Sum of First and Last Digit: " + sum);
    }
}

Output for Negative Number :
Invalid input! Please enter a positive number.

Output for Positive Number (56789) :
First Digit: 5
Last Digit: 9
Sum of First and Last Digit: 14

Here are some Java-related programs that will help you understand Java concepts better:   

Related Posts