Program to delete Nth digit of a Number
Last Updated :
11 Jul, 2025
Given a number num and a number n, the task is to delete this nth digit of the number num, from starting and from end.
Examples:
Input: num = 1234, n = 3
Output: num_after_deleting_from_starting = 124, num_after_deleting_from_end = 134
Input: num = 4516312, n = 2
Output: num_after_deleting_from_starting = 416312, num_after_deleting_from_end = 451632
Approach:
- To delete nth digit from starting:
- Get the number and the nth digit to be deleted.
- Count the number of digits
- Loop number of digits time by counting it with a variable i.
- If the i is equal to (number of digits - n), then skip, else add the ith digit as [ new_number = (new_number * 10) + ith_digit ].
- To delete nth digit from ending:
- Get the number and the nth digit to be deleted.
- Loop number of digits time by counting it with a variable i.
- If the i is equal to (n), then skip, else add the ith digit as [ new_number = (new_number * 10) + ith_digit ].
Implementation:
C++
// C++ implementation of above approach
#include <bits/stdc++.h>
using namespace std;
// Function to delete nth digit
// from starting
int deleteFromStart(int num, int n)
{
// Get the number of digits
int d = log10(num) + 1;
// Declare a variable
// to form the reverse resultant number
int rev_new_num = 0;
// Loop with the number
for (int i = 0; num != 0; i++) {
int digit = num % 10;
num = num / 10;
if (i == (d - n)) {
continue;
}
else {
rev_new_num = (rev_new_num * 10) + digit;
}
}
// Declare a variable
// to form the resultant number
int new_num = 0;
// Loop with the number
for (int i = 0; rev_new_num != 0; i++) {
new_num = (new_num * 10)
+ (rev_new_num % 10);
rev_new_num = rev_new_num / 10;
}
// Return the resultant number
return new_num;
}
// Function to delete nth digit
// from ending
int deleteFromEnd(int num, int n)
{
// Declare a variable
// to form the reverse resultant number
int rev_new_num = 0;
// Loop with the number
for (int i = 1; num != 0; i++) {
int digit = num % 10;
num = num / 10;
if (i == n) {
continue;
}
else {
rev_new_num = (rev_new_num * 10) + digit;
}
}
// Declare a variable
// to form the resultant number
int new_num = 0;
// Loop with the number
for (int i = 0; rev_new_num != 0; i++) {
new_num = (new_num * 10)
+ (rev_new_num % 10);
rev_new_num = rev_new_num / 10;
}
// Return the resultant number
return new_num;
}
// Driver code
int main()
{
// Get the number
int num = 1234;
cout << "Number: " << num << endl;
// Get the digit number to be deleted
int n = 3;
cout << "Digit to be deleted: " << n << endl;
// Remove the nth digit from starting
cout << "Number after " << n
<< " digit deleted from starting: "
<< deleteFromStart(num, n) << endl;
// Remove the nth digit from ending
cout << "Number after " << n
<< " digit deleted from ending: "
<< deleteFromEnd(num, n) << endl;
return 0;
}
// Java implementation of above approach
class GFG
{
// Function to delete nth digit
// from starting
static int deleteFromStart(int num, int n)
{
// Get the number of digits
int d = (int)Math.log10(num) + 1;
// Declare a variable
// to form the reverse resultant number
int rev_new_num = 0;
// Loop with the number
for (int i = 0; num != 0; i++) {
int digit = num % 10;
num = num / 10;
if (i == (d - n)) {
continue;
}
else {
rev_new_num = (rev_new_num * 10) + digit;
}
}
// Declare a variable
// to form the resultant number
int new_num = 0;
// Loop with the number
for (int i = 0; rev_new_num != 0; i++) {
new_num = (new_num * 10)
+ (rev_new_num % 10);
rev_new_num = rev_new_num / 10;
}
// Return the resultant number
return new_num;
}
// Function to delete nth digit
// from ending
static int deleteFromEnd(int num, int n)
{
// Declare a variable
// to form the reverse resultant number
int rev_new_num = 0;
// Loop with the number
for (int i = 1; num != 0; i++) {
int digit = num % 10;
num = num / 10;
if (i == n) {
continue;
}
else {
rev_new_num = (rev_new_num * 10) + digit;
}
}
// Declare a variable
// to form the resultant number
int new_num = 0;
// Loop with the number
for (int i = 0; rev_new_num != 0; i++) {
new_num = (new_num * 10)
+ (rev_new_num % 10);
rev_new_num = rev_new_num / 10;
}
// Return the resultant number
return new_num;
}
// Driver code
public static void main(String []args)
{
// Get the number
int num = 1234;
System.out.println("Number: " + num );
// Get the digit number to be deleted
int n = 3;
System.out.println("Digit to be deleted: " + n );
// Remove the nth digit from starting
System.out.println("Number after " + n
+ " digit deleted from starting: "
+ deleteFromStart(num, n));
// Remove the nth digit from ending
System.out.println( "Number after " + n
+ " digit deleted from ending: "
+ deleteFromEnd(num, n));
}
}
// This code is contributed by ihritik
# Python3 implementation of above approach
# Function to delete nth digit
# from starting
import math;
def deleteFromStart(num, n):
# Get the number of digits
d = (math.log10(num) + 1);
# Declare a variable to form
# the reverse resultant number
rev_new_num = 0;
# Loop with the number
i = 0;
while (num != 0):
digit = num % 10;
num = int(num / 10);
if (i != (int(d) - n)):
rev_new_num = ((rev_new_num * 10) +
digit);
i += 1;
# Declare a variable to form the
# resultant number
new_num = 0;
# Loop with the number
i = 0;
while (rev_new_num != 0):
new_num = ((new_num * 10) +
(rev_new_num % 10));
rev_new_num = int(rev_new_num / 10);
i += 1;
# Return the resultant number
return new_num;
# Function to delete nth digit
# from ending
def deleteFromEnd(num, n):
# Declare a variable to form
# the reverse resultant number
rev_new_num = 0;
# Loop with the number
i = 1;
while (num != 0):
digit = num % 10;
num = int(num / 10);
if (i != n):
rev_new_num = ((rev_new_num * 10) +
digit);
i += 1;
# Declare a variable
# to form the resultant number
new_num = 0;
# Loop with the number
i = 0;
while (rev_new_num != 0):
new_num = ((new_num * 10) +
(rev_new_num % 10));
rev_new_num = int(rev_new_num / 10);
i += 1;
# Return the resultant number
return new_num;
# Driver code
# Get the number
num = 1234;
print("Number:", num);
# Get the digit number to be deleted
n = 3;
print("Digit to be deleted:", n);
# Remove the nth digit from starting
print("Number after", n,
"digit deleted from starting:",
deleteFromStart(num, n));
# Remove the nth digit from ending
print("Number after", n,
"digit deleted from ending:",
deleteFromEnd(num, n));
# This code is contributed by chandan_jnu
// C# implementation of the above approach
using System;
class GFG
{
// Function to delete nth digit
// from starting
static int deleteFromStart(int num, int n)
{
// Get the number of digits
int d = (int)Math.Log10(num) + 1;
// Declare a variable
// to form the reverse resultant number
int rev_new_num = 0;
// Loop with the number
for (int i = 0; num != 0; i++) {
int digit = num % 10;
num = num / 10;
if (i == (d - n)) {
continue;
}
else {
rev_new_num = (rev_new_num * 10) + digit;
}
}
// Declare a variable
// to form the resultant number
int new_num = 0;
// Loop with the number
for (int i = 0; rev_new_num != 0; i++) {
new_num = (new_num * 10)
+ (rev_new_num % 10);
rev_new_num = rev_new_num / 10;
}
// Return the resultant number
return new_num;
}
// Function to delete nth digit
// from ending
static int deleteFromEnd(int num, int n)
{
// Declare a variable
// to form the reverse resultant number
int rev_new_num = 0;
// Loop with the number
for (int i = 1; num != 0; i++) {
int digit = num % 10;
num = num / 10;
if (i == n) {
continue;
}
else {
rev_new_num = (rev_new_num * 10) + digit;
}
}
// Declare a variable
// to form the resultant number
int new_num = 0;
// Loop with the number
for (int i = 0; rev_new_num != 0; i++) {
new_num = (new_num * 10)
+ (rev_new_num % 10);
rev_new_num = rev_new_num / 10;
}
// Return the resultant number
return new_num;
}
// Driver code
public static void Main()
{
// Get the number
int num = 1234;
Console.WriteLine("Number: " + num );
// Get the digit number to be deleted
int n = 3;
Console.WriteLine("Digit to be deleted: " + n );
// Remove the nth digit from starting
Console.WriteLine("Number after " + n
+ " digit deleted from starting: "
+ deleteFromStart(num, n));
// Remove the nth digit from ending
Console.WriteLine( "Number after " + n
+ " digit deleted from ending: "
+ deleteFromEnd(num, n));
}
}
// This code is contributed by ihritik
<?php
//PHP implementation of above approach
// Function to delete nth digit
// from starting
function deleteFromStart($num, $n)
{
// Get the number of digits
$d = (log10($num) + 1);
// Declare a variable
// to form the reverse resultant number
$rev_new_num = 0;
// Loop with the number
for ($i = 0; $num != 0; $i++) {
$digit = $num % 10;
$num = (int)$num / 10;
if ($i == ($d - $n)) {
continue;
}
else {
$rev_new_num = ($rev_new_num * 10) + $digit;
}
}
// Declare a variable
// to form the resultant number
$new_num = 0;
// Loop with the number
for ($i = 0; $rev_new_num != 0; $i++) {
$new_num = ($new_num * 10)
+ ($rev_new_num % 10);
$rev_new_num = (int)$rev_new_num / 10;
}
// Return the resultant number
return $new_num;
}
// Function to delete nth digit
// from ending
function deleteFromEnd($num, $n)
{
// Declare a variable
// to form the reverse resultant number
$rev_new_num = 0;
// Loop with the number
for ($i = 1; $num != 0; $i++) {
$digit = $num % 10;
$num = (int)$num / 10;
if ($i == $n) {
continue;
}
else {
$rev_new_num = ($rev_new_num * 10) + $digit;
}
}
// Declare a variable
// to form the resultant number
$new_num = 0;
// Loop with the number
for ($i = 0; $rev_new_num != 0; $i++) {
$new_num = ($new_num * 10)
+ ($rev_new_num % 10);
$rev_new_num = (int)$rev_new_num / 10;
}
// Return the resultant number
return $new_num;
}
// Driver code
// Get the number
$num = 1234;
echo "Number: " , $num ,"\n";
// Get the digit number to be deleted
$n = 3;
echo "Digit to be deleted: " ,$n ,"\n";
// Remove the nth digit from starting
echo "Number after " , $n,
" digit deleted from starting: ",
deleteFromStart($num, $n),"\n";
// Remove the nth digit from ending
echo "Number after " , $n,
" digit deleted from ending: ",
deleteFromEnd($num, $n) ,"\n";
?>
// This code is contributed by jit_t.
<script>
// Javascript implementation of
// the above approach
// Function to delete nth digit
// from starting
function deleteFromStart(num, n)
{
// Get the number of digits
let d = parseInt(Math.log10(num), 10) + 1;
// Declare a variable
// to form the reverse resultant number
let rev_new_num = 0;
// Loop with the number
for (let i = 0; num != 0; i++) {
let digit = num % 10;
num = parseInt(num / 10, 10);
if (i == (d - n)) {
continue;
}
else {
rev_new_num = (rev_new_num * 10) + digit;
}
}
// Declare a variable
// to form the resultant number
let new_num = 0;
// Loop with the number
for (let i = 0; rev_new_num != 0; i++) {
new_num = (new_num * 10)
+ (rev_new_num % 10);
rev_new_num = parseInt(rev_new_num / 10, 10);
}
// Return the resultant number
return new_num;
}
// Function to delete nth digit
// from ending
function deleteFromEnd(num, n)
{
// Declare a variable
// to form the reverse resultant number
let rev_new_num = 0;
// Loop with the number
for (let i = 1; num != 0; i++) {
let digit = num % 10;
num = parseInt(num / 10, 10);
if (i == n) {
continue;
}
else {
rev_new_num = (rev_new_num * 10) + digit;
}
}
// Declare a variable
// to form the resultant number
let new_num = 0;
// Loop with the number
for (let i = 0; rev_new_num != 0; i++) {
new_num = (new_num * 10)
+ (rev_new_num % 10);
rev_new_num = parseInt(rev_new_num / 10, 10);
}
// Return the resultant number
return new_num;
}
// Get the number
let num = 1234;
document.write("Number: " + num + "</br>");
// Get the digit number to be deleted
let n = 3;
document.write("Digit to be deleted: " + n + "</br>");
// Remove the nth digit from starting
document.write("Number after " + n
+ " digit deleted from starting: "
+ deleteFromStart(num, n) + "</br>");
// Remove the nth digit from ending
document.write( "Number after " + n
+ " digit deleted from ending: "
+ deleteFromEnd(num, n));
</script>
Output: Number: 1234
Digit to be deleted: 3
Number after 3 digit deleted from starting: 124
Number after 3 digit deleted from ending: 134
Complexity Analysis:
Time complexity: O(log(N)).
Auxiliary Space: O(1), since no extra space has been taken.
Another Approach: (To convert number into string)
C++
// C++ implementation to delete nth digit
// from starting with O(logN) time complexity.
#include<bits/stdc++.h>
using namespace std;
// function to delete nth number from starting
static string fromStart(string inp, int del)
{
string inp1 = inp.substr(0, del - 1);
string inp2 = inp.substr(del, inp.length());
return inp1 + inp2;
}
// function to delete nth number from ending
static string fromEnd(string inp, int del)
{
string inp1 = inp.substr(0, inp.length() - del);
string inp2 = inp.substr(inp.length() - del + 1,
inp.length());
return inp1 + inp2;
}
// Driver Code
int main()
{
int in = 1234;
// type cast input number to string
stringstream ss;
ss << in;
string inp = ss.str();
int del = 3;
cout << "num_after_deleting_from_starting "
<< fromStart(inp, del) << endl;
cout << "num_after_deleting_from_ending "
<< fromEnd(inp, del) << endl;
return 0;
}
// This code is contributed by chandan_jnu
// Java implementation to delete nth digit
// from starting with O(logN) time complexity.
public class DeleteN {
public static void main(String args[]) {
int in = 1234;
// type cast input number to string
String inp = Integer.toString(in);
int del = 3;
System.out.println("num_after_deleting_from_starting " + fromStart(inp, del));
System.out.println("num_after_deleting_from_ending " + fromEnd(inp, del));
}
// function to delete nth number from starting
static String fromStart(String inp, int del) {
try {
String inp1 = inp.substring(0, del - 1);
String inp2 = inp.substring(del, inp.length());
return inp1 + inp2;
}
catch (Exception e) {
return "Check Input";
}
}
// function to delete nth number from ending
static String fromEnd(String inp, int del) {
try {
String inp1 = inp.substring(0, inp.length() - del);
String inp2 = inp.substring(inp.length() - del + 1, inp.length());
return inp1 + inp2;
}
catch (Exception e) {
return "Check Input";
}
}
}
# Python3 implementation to delete nth digit
# from starting with O(logN) time complexity.
# function to del1ete nth number
# from starting
def fromStart(inp, del11):
inp1 = inp[0:del1 - 1];
inp2 = inp[del1:len(inp)];
return inp1 + inp2;
# function to delete nth number
# from ending
def fromEnd(inp, del1):
inp1 = inp[0:len(inp) - del1];
inp2 = inp[len(inp) - del1 + 1:len(inp)];
return inp1 + inp2;
# Driver Code
in1 = 1234;
# type cast input number to string
inp = str(in1);
del1 = 3;
print("num_after_deleting_from_starting",
fromStart(inp, del1));
print("num_after_deleting_from_ending",
fromEnd(inp, del1));
# This code is contributed by chandan_jnu
// C# implementation to delete nth digit
// from starting with O(logN) time complexity.
using System ;
public class DeleteN {
public static void Main() {
int num = 1234;
// type cast input number to string
string inp = Convert.ToString(num) ;
int del = 3;
Console.WriteLine("num_after_deleting_from_starting "
+ fromStart(inp, del));
Console.WriteLine("num_after_deleting_from_ending "
+ fromEnd(inp, del));
}
// function to delete nth number from starting
static String fromStart(string inp, int del) {
try {
string inp1 = inp.Substring(0, del - 1);
string inp2 = inp.Substring(del, inp.Length - del);
return inp1 + inp2;
}
catch (Exception ) {
return "Check Input";
}
}
// function to delete nth number from ending
static String fromEnd(string inp, int del) {
try {
string inp1 = inp.Substring(0, inp.Length - del);
string inp2 = inp.Substring(inp.Length - del + 1, del - 1);
return inp1 + inp2;
}
catch (Exception e) {
Console.WriteLine(e) ;
return "Check Input";
}
}
}
// This code is contributed by Ryuga
<?php
// PHP implementation to delete nth digit
// from starting with O(logN) time complexity.
// function to delete nth number from starting
function fromStart($inp, $del)
{
$inp1 = substr($inp, 0, $del - 1);
$inp2 = substr($inp, $del, strlen($inp));
return $inp1.$inp2;
}
// function to delete nth number from ending
function fromEnd($inp, $del)
{
$inp1 = substr($inp, 0, strlen($inp) - $del);
$inp2 = substr($inp, strlen($inp) - $del + 1,
strlen($inp));
return $inp1.$inp2;
}
// Driver Code
$in = 1234;
// type cast input number to string
$inp = strval($in);
$del = 3;
print("num_after_deleting_from_starting " .
fromStart($inp, $del) . "\n");
print("num_after_deleting_from_ending " .
fromEnd($inp, $del));
// This code is contributed by chandan_jnu
?>
<script>
// Javascript implementation to delete nth digit
// from starting with O(logN) time complexity.
// function to delete nth number from starting
function fromStart(inp, del) {
let inp1 = inp.substring(0, del - 1);
let inp2 = inp.substring(del, inp.length);
return inp1 + inp2;
}
function fromEnd(inp, del) {
let inp1 = inp.substring(0, inp.length - del);
let inp2 = inp.substring(inp.length - del + 1, inp.length - del + 1 + inp.length);
return inp1 + inp2;
}
let In = 1234;
// type cast input number to string
let inp = In.toString();
let del = 3;
document.write("num_after_deleting_from_starting " + fromStart(inp, del) + "</br>");
document.write("num_after_deleting_from_ending " + fromEnd(inp, del) + "</br>");
// This code is contributed by mukesh07.
</script>
Output:
num_after_deleting_from_starting 124
num_after_deleting_from_ending 134
Time complexity :O(log(N)).
Auxiliary Space: O(log(N)).
C++ Program to Delete Nth Digit of a Number
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GeometryGeometry is a branch of mathematics that studies the properties, measurements, and relationships of points, lines, angles, surfaces, and solids. From basic lines and angles to complex structures, it helps us understand the world around us.Geometry for Students and BeginnersThis section covers key br
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