- Write a C program to find sum of first and last digits of a number.
- Wap in C to find sum of least significant and most significant digit of a number.
Required Knowledge
- C printf and scanf functions
- While loop in C
Python get last digit of int: To get the least significant digit of a number we will use ‘%’ modulus operator. Number%10 will give the least significant digit of the number. Then we will remove one digit at a time form number using below mentioned algorithm and then store the most significant digit in firstDigit variable.
Sum of first and last digits of 2534 = 2 + 4 = 6
Algorithm to find first and last digits of a number
- Get least significant digit of number (number%10) and store it in lastDigit variable.
- Remove least significant digit form number (number = number/10).
- Repeat above two steps, till number is greater than 10.
- The remaining number is the first digit of number.
C program to find sum of first and last digits of a number

#include <stdio.h>
int main() {
int num, temp, firstDigit, lastDigit;
/*
* Take a number as input from user
*/
printf("Enter a Number\n");
scanf("%d", &num);
temp = num;
/* get last digit of num */
lastDigit = num %10;
while(num > 10){
/* Keep on removing the last digit untill
num becomes less than 10(single digit) */
num = num/10;
}
firstDigit = num;
printf("Sum of first and last digit of %d = %d", temp, firstDigit+lastDigit);
getch();
return 0;
}
Output
Enter a Number 2436 Sum of first and last digit of 2436 = 8
Enter a Number 2222 Sum of first and last digit of 2222 = 4
Write a C program to find product of digits of a number using while loop.
Wap in C to multiply the digits of a number.
Required Knowledge
- C printf and scanf functions
- While loop in C
To multiply digits of a number we have to remove one digit at a time, we can use ‘/’ division and ‘%’ modulus operator. Number%10 will give the least significant digit of the number, we will use it to get one digit of number at a time. To remove last least significant digit from number we will divide number by 10.
Product of digits of 2534 = 2 x 5 x 3 x 4 = 120
Algorithm to find product of digits of a number
- Get least significant digit of number (number%10) and multiply it to the product variable.
- Remove least significant digit form number (number = number/10).
- Repeat above two steps, till number is not equal to zero.
C program to find sum of all even numbers between 1 to N using for loop

#include <stdio.h>
#include <conio.h>
int main() {
int num, temp;
long productOfDigit = 1;
/*
* Take a number as input from user
*/
printf("Enter a Number\n");
scanf("%d", &num);
temp = num;
while(num != 0){
/* get the least significant digit(last digit)
of number and multiply it to productofDigit */
productOfDigit *= num % 10;
/* remove least significant digit(last digit)
form number */
num = num/10;
}
printf("Product of digits of %d = %ld", temp, productOfDigit);
getch();
return 0;
}
Output
Enter a Number 2436 Product of digits of 2436 = 144
Enter a Number 2222 Product of digits of 2436 = 16