Given a number to find the 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 find 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):
// 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;
} |
// 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 |
# 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 |
// 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 |
<?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) |
<script> // javascript 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 Math.floor(n);
}
// Find the last digit
function lastDigit(n)
{
// return the last digit
return Math.floor(n % 10);
}
// Driver code let n = 98562;
document.write(firstDigit(n) + " "
+ lastDigit(n));
// This code is contributed by sanjoy_62.
</script> |
9 2
Time Complexity: O(log10n)
Auxiliary Space: O(1)
Approach 2 (Without loop)
// 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;
} |
// 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. |
# 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 |
// 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. |
<?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 ?> |
<script> // JavaScript program to find first // and last digits of a number // Find the first digit function firstDigit(n)
{ // Find total number of digits - 1
let digits = Math.floor(Math.log(n)/Math.log(10))
// Find first digit
n = Math.floor(n / Math.pow(10, digits))
// Return first digit
return n;
} // Find the last digit function lastDigit(n){
// return the last digit
return (n % 10)
} // Driver Code let n = 98562; document.write(firstDigit(n), " " )
document.write(lastDigit(n), "</br>" )
// This code is contributed by shinjanpatra </script> |
9 2
Time Complexity: O(log(log10(n))
Auxiliary Space: O(1)
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.
Approach 3: Using string operation to_string
First converting number to string and then first char of string and last character of string – ‘0’ is our ans.
#include <iostream> using namespace std;
int main() {
int n = 34356;
string s = to_string(n);
int first_digit = s.front() - '0' ;
int last_digit = s.back() - '0' ;
cout<< "First digit of " <<n<< " is " <<first_digit<<endl;
cout<< "Last digit of " <<n<< " is " <<last_digit<<endl;
} |
import java.util.*;
public class Main {
public static void main(String[] args) {
int n = 34356 ;
String s = Integer.toString(n);
int first_digit = s.charAt( 0 ) - '0' ;
int last_digit = s.charAt(s.length() - 1 ) - '0' ;
System.out.println( "First digit of " + n + " is " + first_digit);
System.out.println( "Last digit of " + n + " is " + last_digit);
}
} |
# Python program to extract first and last digits of a number # including comments and no empty lines # take an integer input n = 34356
# convert the integer to string s = str (n)
# extract first and last digits from the string first_digit = int (s[ 0 ])
last_digit = int (s[ - 1 ])
# print the results print ( "First digit of" , n, "is" , first_digit)
print ( "Last digit of" , n, "is" , last_digit)
|
using System;
public class GFG{
static public void Main (){
int n = 34356;
string s = n.ToString();
int first_digit = s[0] - '0' ;
int last_digit = s[s.Length - 1] - '0' ;
Console.WriteLine( "First digit of {0} is {1}" , n, first_digit);
Console.WriteLine( "Last digit of {0} is {1}" , n, last_digit);
}
} |
let n = 34356; let s = n.toString(); let first_digit = parseInt(s.charAt(0)); let last_digit = parseInt(s.charAt(s.length-1)); console.log( "First digit of " + n + " is " + first_digit);
console.log( "Last digit of " + n + " is " + last_digit);
|
First digit of 34356 is 3 Last digit of 34356 is 6
Time Complexity: O(n)
Auxiliary Space: O(n)