# Sum of First and Last Digit of a Number in Java

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;

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
Scanner scan =  new Scanner(System.in);

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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