C Program to Find Sum of First and Last Digit Of a Number

How to write a C Program to Find Sum of First and Last Digit Of a Number with an example?.

C Program to Find Sum of First and Last Digit Of a Number

This program allows the user to enter any number. And then, it is going to find the Sum of First Digit and Last Digit of the user-entered value.

/* C Program to Find Sum of First and Last Digit Of a Number */
 
#include <stdio.h>
#include <math.h>
 
int main()
{
  	int Number, FirstDigit, Count, LastDigit, Sum = 0;
 
  	printf("\n Please Enter any Number that you wish  : ");
  	scanf("%d", & Number);
  	
  	Count = log10(Number); 	
  	FirstDigit = Number / pow(10, Count);
  	
  	LastDigit = Number % 10;
  	
  	Sum = FirstDigit + LastDigit;
	    
	printf(" \n The Sum of First Digit (%d) and Last Digit (%d) of %d =  %d", FirstDigit, LastDigit, Number, Sum);
 
  	return 0;
}

In this above C Programming example, Number = 2345

Count = log10(Number) = 3
FirstDigit = 2345 / pow(10, 3) = 2345 / 1000 = 2.345 = 2
LastDigit = 2345 % 10 = 5

Sum = 2 + 5 = 7

Program to Find Sum of First and Last Digit Of a Number Example 2

This C program will use While Loop to find the First Digit of the user entered value. We already explained the Analysis part in our previous articles. So, Please refer First Digit and Last Digit article to understand the same.

/* C Program to Find Sum of First and Last Digit Of a Number */
 
#include <stdio.h>
 
int main()
{
  	int Number, FirstDigit, LastDigit, Sum = 0;
 
  	printf("\n Please Enter any Number that you wish  : ");
  	scanf("%d", & Number);
  	
  	FirstDigit = Number;
  	
  	while(FirstDigit >= 10)
  	{
  		FirstDigit = FirstDigit / 10;
	}
  	
  	LastDigit = Number % 10;
  	
  	Sum = FirstDigit + LastDigit;
	    
	printf(" \n The Sum of First Digit (%d) and Last Digit (%d) of %d =  %d", FirstDigit, LastDigit, Number, Sum);
 
  	return 0;
}

 Please Enter any Number that you wish  : 45896
 
 The Sum of First Digit (4) and Last Digit (6) of 45896 =  10

C Program to calculate Sum of First and Last Digit Of a Number using Function

This program to calculate sum of first and last digit is the same as above, but this time we divided the code using the Functions concept.

/* C Program to Find Sum of First and Last Digit Of a Number */
 
#include <stdio.h>

int First_Digit(int num);
int Last_Digit(int num); 

int main()
{
  	int Number, FirstDigit, LastDigit, Sum = 0;
 
  	printf("\n Please Enter any Number that you wish  : ");
  	scanf("%d", & Number);
  	
  	FirstDigit = First_Digit(Number);
  	LastDigit = Last_Digit(Number);

  	Sum = FirstDigit + LastDigit;
	    
	printf(" \n The Sum of First Digit (%d) and Last Digit (%d) of %d =  %d", FirstDigit, LastDigit, Number, Sum);
 
  	return 0;
}

int First_Digit(int num)
{
	while(num >= 10)
	{
		num = num / 10;
	}
	return num;
}

int Last_Digit(int num)
{
	return num % 10;
}

 Please Enter any Number that you wish  : 45862
 
 The Sum of First Digit (4) and Last Digit (2) of 45862 =  6