Find first and last digits of a number

Given a number and to find first and last digit of a number.

Examples:

Input : 12345 
Output : First digit: 1
         last digit : 5

Input : 98562
Output : First digit: 9
         last digit : 2



To find last digit of a number, we use modulo operator %. When modulo divided by 10 returns its last digit.
Suppose if n = 1234
then last Digit = n % 10 => 4
To finding first digit of a number is little expensive than last digit. To find first digit of a number we divide the given number by 10 until number is greater than 10. At the end we are left with the first digit.

Approach 1 (With loop):

C++

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// Program to find first and last
// digits of a number
#include <bits/stdc++.h>
using namespace std;
  
// Find the first digit
int firstDigit(int n)
{
    // Remove last digit from number
    // till only one digit is left
    while (n >= 10) 
        n /= 10;
      
    // return the first digit
    return n;
}
  
// Find the last digit
int lastDigit(int n)
{
    // return the last digit
    return (n % 10);
}
  
// Driver program
int main()
{
    int n = 98562;
    cout << firstDigit(n) << " " 
        << lastDigit(n) << endl;
    return 0;
}

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Java

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// Java Program to find first and last
// digits of a number
import java.util.*;
import java.lang.*;
  
public class GfG{
      
    // Find the first digit
    public static int firstDigit(int n)
    {
        // Remove last digit from number
        // till only one digit is left
        while (n >= 10
            n /= 10;
      
        // return the first digit
        return n;
    }
  
    // Find the last digit
    public static int lastDigit(int n)
    {
        // return the last digit
        return (n % 10);
    }
      
    // driver function
    public static void main(String argc[])
    {
        int n = 98562;
        System.out.println(firstDigit(n) + " "
        + lastDigit(n));
    }
}
  
// This code is contributed by Sagar Shukla

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Python3

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# Python3 program to find first and 
# last digits of a number
  
# Find the first digit
def firstDigit(n) :
  
    # Remove last digit from number
    # till only one digit is left
    while n >= 10
        n = n / 10;
      
    # return the first digit
    return int(n)
  
# Find the last digit
def lastDigit(n) :
  
    # return the last digit
    return (n % 10)
  
# Driver Code
n = 98562;
print(firstDigit(n), end = " "
print(lastDigit(n))
  
# This code is contributed by rishabh_jain

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C#

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// C# Program to find first and last
// digits of a number
using System;
  
public class GfG{
      
    // Find the first digit
    public static int firstDigit(int n)
    {
        // Remove last digit from number
        // till only one digit is left
        while (n >= 10) 
            n /= 10;
      
        // return the first digit
        return n;
    }
  
    // Find the last digit
    public static int lastDigit(int n)
    {
        // return the last digit
        return (n % 10);
    }
      
    // driver function
    public static void Main()
    {
        int n = 98562;
        Console.WriteLine(firstDigit(n) + " "
        + lastDigit(n));
    }
}
  
// This code is contributed by vt_m

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PHP

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<?php
// PHP Program to find first 
// and last digits of a number
  
// Find the first digit
function firstDigit($n)
{
    // Remove last digit from number
    // till only one digit is left
    while ($n >= 10) 
        $n /= 10;
      
    // return the first digit
    return (int)$n;
}
  
// Find the last digit
function lastDigit($n)
{
    // return the last digit
    return ((int)$n % 10);
}
  
// Driver Code
$n = 98562;
echo firstDigit($n) . " " .
     lastDigit($n) . "\n";
  
// This code is contributed 
// by Akanksha Rai(Abby_akku)

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Output:

9 2

 

Approach 2 (Without loop)

C++

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// Program to find first and last 
// digits of a number
#include <bits/stdc++.h>
using namespace std;
  
// Find the first digit
int firstDigit(int n)
{
    // Find total number of digits - 1
    int digits = (int)log10(n);
  
    // Find first digit
    n = (int)(n / pow(10, digits));
  
    // Return first digit
    return n;
}
  
// Find the last digit
int lastDigit(int n)
{
    // return the last digit
    return (n % 10);
}
  
// Driver program
int main()
{
    int n = 98562;
    cout << firstDigit(n) << " " 
         << lastDigit(n) << endl;
    return 0;
}

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Java

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// Java program to find first and 
// last  digits of a number
import java.math.*;
  
class GFG {
      
    // Find the first digit
    static int firstDigit(int n)
    {
        // Find total number of digits - 1
        int digits = (int)(Math.log10(n));
      
        // Find first digit
        n = (int)(n / (int)(Math.pow(10, digits)));
      
        // Return first digit
        return n;
    }
      
    // Find the last digit
    static int lastDigit(int n)
    {
        // return the last digit
        return (n % 10);
    }
      
    // Driver program
    public static void main(String args[])
    {
        int n = 98562;
        System.out.println(firstDigit(n) +
                           " " + lastDigit(n));
    }
}
  
  
// This code is contributed by Nikita Tiwari.

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Python3

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# Python3 program to find first  
# and last digits of a number
import math
  
# Find the first digit
def firstDigit(n) :
      
    # Find total number of digits - 1
    digits = (int)(math.log10(n))
  
    # Find first digit
    n = (int)(n / pow(10, digits))
  
    # Return first digit
    return n;
  
# Find the last digit
def lastDigit(n) :
      
    # return the last digit
    return (n % 10)
  
# Driver Code
n = 98562;
print(firstDigit(n), end = " "
print(lastDigit(n))
  
# This code is contributed by rishabh_jain

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C#

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// C# program to find first and 
// last digits of a number
using System;
  
class GFG {
      
    // Find the first digit
    static int firstDigit(int n)
    {
        // Find total number of digits - 1
        int digits = (int)(Math.Log10(n));
      
        // Find first digit
        n = (int)(n / (int)(Math.Pow(10, digits)));
      
        // Return first digit
        return n;
    }
      
    // Find the last digit
    static int lastDigit(int n)
    {
        // return the last digit
        return (n % 10);
    }
      
    // Driver program
    public static void Main()
    {
        int n = 98562;
        Console.WriteLine(firstDigit(n) +
                        " " + lastDigit(n));
    }
}
  
  
// This code is contributed by vt_m.

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PHP

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<?php
// Program to find first and last 
// digits of a number 
  
// Find the first digit 
function firstDigit($n
    // Find total number of digits - 1 
    $digits = (int)log10($n); 
  
    // Find first digit 
    $n = (int)($n / pow(10, $digits)); 
  
    // Return first digit 
    return $n
  
// Find the last digit 
function lastDigit($n
    // return the last digit 
    return ($n % 10); 
  
// Driver Code 
$n = 98562; 
echo firstDigit($n) , " ",
     lastDigit($n), "\n"
  
// This code is contributed by ajit
?>

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Output:

9 2

Important note: log10() is a mathematical function present in math.h header file. It returns log base 10 value of the passed parameter to log10() function.



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Improved By : jit_t, Akanksha_Rai