➤ Check Even Number
➤ Check Odd Number
➤ Java Even-Odd
➤ Greatest of 3 numbers
➤ Exponents in Java
➤ Java Leap Year Program
➤ Display Multiplication Table
➤ Reverse of a number
➤ Factors of a Number
➤ Java LCM of 2 Numbers
➤ Java HCF of 2 Numbers
➤ Quadratic Equation Program
➤ Square Root of Number
➤ Perfect Square Program
➤ Simple Calculator Program
➤ BMI Calculator Java
➤ Factorial of a Number
➤ Factorial Using Recursion
# Java Programs to Find Sum
# Java Conversion Programs
# Java Program on Series
# Java Pattern Programs
# Java Number Programs
Java Array Programs
Java String Programs
Previously we have written a Java program to find the sum of digits of the given number. Now in this post, we will write a Java program to find the sum of the first and last digit of a number.
Example:-
Number = 12345
The first digit = 1, last digit = 5
Sum of first and last digits = 1 + 5 = 6
Procedure to find the sum of first and last digit of a number in java,
- Take a number
- Declare sum variable and initialize it with 0
- Find the last digit. To find the last digit we can use % operator. The expression
number%10
gives the last digit of the number. - Find the first digit of the number. For this
- Find the total number of digits in the given number.
- Divide the number by
10^(total_number_of_digits-1)
, it will give the first digit of the number.
- Add first and the last digit to the sum variable.
How to find or get the last digit of a number in java?
You can easily find the last digit of a number in Java using % operator. Any number%10 gives the last digit of the number. Below code in Java is used to get the last digit of a number,
int number = 1234;
int last_digit = number % 10;
So, last_digit = 1234 % 10 = 4
How to find or get the first digit of a number in Java?
To find or get the first digit of a number in Java, First of all, we need to count the total number of digits in the given number.
int
number = 1234;
So, total_digits = 4;
After calculating number of digits, calculate the power of 10 ^ (total_digits-1)
int divisor = (int) Math.pow(10, total_digits-1);
int first_digit = number / divisor;
So, divisor = (int)Math.pow(10, 3) = 1000
The return type of the pow(-,-)
method of Math class is double. We are working with integer values so convert it into an integer using type-casting. You can also use your own method to find the power of a given number. Now, divide the number using the power value.
So, first_digit = 1234 / 1000 = 1
Java Program to find the sum of first and last digit of the number
import java.util.Scanner;
public class SumOfFirstAndLastDigitProgram {
// method to find sum of first and last digit
private static int FirstLastDigitSum(int number) {
// declare variables
int lastDigit, firstDigit, divisor;;
int totalDigits = 0;
int sum = 0;
// find last digit
lastDigit = number%10;
// find total number of digits
totalDigits = findDigits(number);
// calculate divisor value
divisor = (int)Math.pow(10, totalDigits-1);
// find first digit
firstDigit = number / divisor;
// add values
sum = firstDigit + lastDigit;
return sum;
}
// method to find total number of digits
private static int findDigits(int number) {
int count = 0;
while(number!=0) {
count++;
number = number/10;
}
return count;
}
public static void main(String[] args) {
// declare variables
int number = 0;
int sum = 0;
// create Scanner class object
// for reading the values
Scanner scan = new Scanner(System.in);
// read input
System.out.print("Enter an integer number:: ");
number = scan.nextInt();
// find sum of digits of number
sum = FirstLastDigitSum(number);
// display result
System.out.println("The sum of first & last"
+" digit of the number "+number
+" = "+ sum);
// close Scanner class object
scan.close();
}
}
The output for the different test-cases:-
Enter an integer number:: 213457
The sum of first & last digit of the number 213457 = 9
Enter an integer number:: 456
The sum of first & last digit of the number 456 = 10
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