In this post, we will learn how to find the first and the last digit of a number using C Programming language.
We will use following approaches to find the first and last digit of a number:
- Using Loop
- Without Using Loop
- Using Functions
So, without further ado, let’s begin this tutorial.
C Program to Find First and Last Digit of a Number
// C Program to Find First and Last Digit of a Number
#include <stdio.h>
int main(){
int num, firstDigit, lastDigit;
// Asking for input
printf("Enter a number: ");
scanf("%d", &num);
// Finding last digit of a number
lastDigit = num % 10;
// Finding first digit of a number
firstDigit = num;
while (firstDigit >= 10){
firstDigit = firstDigit / 10;
}
// Displaying output
printf("First digit of the entered number is: %d \n", firstDigit);
printf("Last digit of the entered number is: %d", lastDigit);
return 0;
}
Output
Enter a number: 247
First digit of the entered number is: 2
Last digit of the entered number is: 7
How Does This Program Work?
int num, firstDigit, lastDigit;
In this program, we have declared three int data type variables named num, firstDigit and lastDigit.
// Asking for input
printf("Enter a number: ");
scanf("%d", &num);
The user is asked to enter a positive number. This number gets stored in the num named variable.
// Finding last digit of a number
lastDigit = num % 10;
We find the last digit of the entered number with the help of (%) Modulus operator. When the entered number is divided by 10, then it returns the remainder which is the last digit of a number.
// Finding first digit of a number
firstDigit = num;
while (firstDigit >= 10){
firstDigit = firstDigit / 10;
}
We find the first digit of the entered number with the help of (/) division operator. We divide the entered number by 10 until the number is greater than 10. When the number becomes less than 10, we get the first digit.
// Displaying output
printf("First digit of the entered number is: %d \n", firstDigit);
printf("Last digit of the entered number is: %d", lastDigit);
At the end, the first and last digit of the entered number is printed on the screen using printf() function.
C Program to Find First and Last Digit of a Number Without Using Loops
// C Program to Find First and Last Digit of a Number Without Using Loops
#include <stdio.h>
int main(){
int num, firstDigit, lastDigit, count;
// Asking for input
printf("Enter a positive number: ");
scanf("%d", &num);
// Finding last digit
lastDigit = num % 10;
// Finding first digit
count = (int)log10(num);
firstDigit = (int)(num / pow(10, count));
// Displaying output
printf("First Digit of the entered number is: %d \n", firstDigit);
printf("Last Digit of the entered number is: %d", lastDigit);
return 0;
}
Output
Enter a positive number: 548
First Digit of the entered number is: 5
Last Digit of the entered number is: 8
C Program to Find First and Last Digit of a Number Using Functions
// C Program to Find First and Last Digit of a Number Using Functions
#include <stdio.h>
int first_digit(int n){
while (n >= 10){
n = n / 10;
}
return n;
}
int last_digit(int n){
return n % 10;
}
int main(){
int num, firstDigit, lastDigit;
// Asking for input
printf("Enter a number: ");
scanf("%d", &num);
// Calling out user-defined functions
firstDigit = first_digit(num);
lastDigit = last_digit(num);
// Displaying output
printf("The first digit of the entered number is: %d \n", firstDigit);
printf("The last digit of the entered number is: %d", lastDigit);
return 0;
}
Output
Enter a number: 456
The first digit of the entered number is: 4
The last digit of the entered number is: 6
Conclusion
I hope after going through this post, you understand how to find the first and the last digit of a number using C Programming language.
If you have any doubt regarding the program, then contact us in the comment section. We will be delighted to solve your query.
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