# C program to find sum of first and last digit of a number

Learn how to write a C program to find the sum of the first and last digit of a number. This article provides a detailed explanation and sample code for this basic yet essential task in C programming.

Finding the sum of the first and last digits of a number is a common problem in programming that helps in understanding basic arithmetic operations and control structures. In this article, we will guide you through writing a C program to find the sum of the first and last digits of a given number, providing a detailed explanation and sample code.

## Steps to Find the Sum of the First and Last Digit

To solve this problem, follow these steps:

**Input the Number**: Read the number from the user.**Extract the Last Digit**: Find the number's last digit using the modulus operator.**Extract the First Digit**: Find the first digit by continuously dividing the number by 10 until the number is less than 10.**Calculate the Sum**: Add the first and last digits.**Print the Result**: Output the sum to the console.

## Write a C program to find sum of first and last digits of a number

Here's a C program to find the sum of the first and last digit of a number:

```
#include <stdio.h>
int main() {
int number, firstDigit, lastDigit, sum;
// Input the number
printf("Enter an integer: ");
scanf("%d", &number);
// Extract the last digit
lastDigit = number % 10;
// Extract the first digit
firstDigit = number;
while (firstDigit >= 10) {
firstDigit /= 10;
}
// Calculate the sum
sum = firstDigit + lastDigit;
// Print the result
printf("Sum of the first and last digit: %d", sum);
return 0;
}
```

**Output**

```
Enter an integer: 1234
Sum of the first and last digit: 5
```

### Explanation

**Input the Number**: The program prompts the user to enter an integer. The`scanf`

function reads the input number and stores it in the variable`number`

.**Extract the Last Digit**:- The last digit is found using the modulus operator (
`%`

), which gives the remainder when`number`

is divided by 10. - For example, if the number is 1234,
`lastDigit = 1234 % 10`

will result in`lastDigit = 4`

.

- The last digit is found using the modulus operator (
**Extract the First Digit**:- The first digit is found by repeatedly dividing the number by 10 until it is less than 10.
- For example, if the number is 1234, the sequence of operations will be
`1234 / 10 = 123`

,`123 / 10 = 12`

,`12 / 10 = 1`

, resulting in`firstDigit = 1`

.

**Calculate the Sum**: The sum of the first and last digits is calculated by adding`firstDigit`

and`lastDigit`

.**Print the Result**: The program prints the sum to the console using the`printf`

function.

### Detailed Steps

**Step 1: Input the Number**- Use
`printf`

to prompt the user for input. - Use
`scanf`

to read the number from the user.

- Use
**Step 2: Extract the Last Digit**- Use the modulus operator (
`%`

) to get the last digit of the number.

- Use the modulus operator (
**Step 3: Extract the First Digit**- Use a
`while`

loop to divide the number by 10 until it is less than 10.

- Use a
**Step 4: Calculate the Sum**- Add the first and last digits.

**Step 5: Print the Result**- Use
`printf`

to display the sum of the first and last digits.

- Use