C++ Program to Reverse a Number

C++ reverse number – C++ Program to Reverse a Number

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C++ reverse number: In the previous article, we have discussed about C++ Program to Calculate Power of a Number. Let us learn how to Reverse a Number in C++ Program.

Methods to Reverse a Number in C++

How to reverse a number c++: In this article, we will see different methods of how we can reverse a number in c++. Let see all the methods one by one.

Method1-Using while loop

get4321.com: In this method, we extract the digit of a number a through this we will make a new number which is the reverse of the given number. Let’s write the code to understand this.

#include <iostream>
using namespace std;

int main() {
    int n, reversedNumber = 0, remainder;
    n=1234;
    while(n != 0) {
        remainder = n%10;
        reversedNumber = reversedNumber*10 + remainder;
        n /= 10;
    }
    cout << "Reversed Number = " << reversedNumber;

    return 0;
}

Output

Reversed Number = 4321

Now lets see how this work. Suppose our number is 1234.

Iteration1- remainder-4  reversedNumber=(0*10)+4=4    number=1234/10=123

Iteration2- remainder-3  reversedNumber=(4*10)+3=43    number=123/10=12

iteration3- remainder-2   reversedNumber=(43*10)+2=432   number=12/10=1

iteration4- remainder-1    reversedNumber=(432*10)+1=4321   number=1/10=0

As the number become 0 so we come out of the loop and we get 4321 as our reversed number.

Method 2-By converting number to string

In this method first, we convert our number to a string. For this we use inbuilt method in c++ to_string().Then we reverse the string using the reverse() method in c++. And then we convert that reverse string again to a number using stoi() method. Let write the code for this.

#include <bits/stdc++.h>
using namespace std;

int main() {
    int n, reversedNumber = 0, remainder;
    n=1234;
    string s=to_string(n);
    reverse(s.begin(),s.end());
    n=stoi(s);
    cout << "Reversed Number = " << n;
    return 0;
}

Output

Reversed Number = 4321

So these are the methods to reverse a number in c++.