How to Reverse integers using 'for loop' and an 'array' in C#

Question

I am new to C# and I am learning to reverse integers (numbers). I have to use forloop and an array to complete the code but i really have no idea how to use those.
For example. If the input is: 1 2 3 4 5 6
Results should be : 6 5 4 3 2 1

Can someone please help me. Thank you :)

Edit: I am really sorry guys, I forgot to add the code. Here it is. Thanks again

static void Main(string[] args)
{
    Console.WriteLine("Enter 6 Numbers");
    int numb = int.Parse(Console.ReadLine());
    int reverse = 0;
    while (numb > 0)
    {
        int rem = numb % 10;
        reverse = (reverse * 10) + rem;
        numb = numb / 10;
    }

    Console.WriteLine("The reverse is = {0}", reverse);
    Console.ReadLine();
}

Edit

Here a string is taken as input and need to be reversed. Just due to the input is taken as numbers only so this is confusing little bit.

Are you trying to reverse integers in an array, or reverse digits in an integer? It seems to me that your words say one thing, yet your code says another entirely. — David Frye
– David Frye, Commented Aug 14, 2014 at 1:22
Unclear how title related to sample - there is arrays and no "integers"... You may need to look at existing question about reading array of integers first... To match title your code sample should show one method with signature: int[] Reverse(int[] source) or maybe void ReverseInPlace(int[] array). — Alexei Levenkov
– Alexei Levenkov, Commented Aug 14, 2014 at 1:43

Cyral · Accepted Answer · 2014-08-14 01:19:33Z

4

Unless you need to use a loop, a much simpler solution is to use Array.Reverse:

int[] array = { 1, 2, 3, 4, 5, 6 };
Array.Reverse(array);

You could use a for loop and iterate half of the array, switching the positions with the ones on the opposite side of the array.

int holder = 0;
int size = array.Length;
for (int i = 0; i < size / 2; ++i)
{
    holder = array[i];
    array[i] = array[size - 1 - i];
    array[size - 1 - i] = holder;
}

edited Aug 14, 2014 at 1:19

answered Aug 14, 2014 at 1:08

Cyral

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Comments

Purushoth · Accepted Answer · 2018-02-15 08:19:56Z

Here is a simple logic to Reverse Numbers/Integers using Loops and using Array.Reverse Functionality

Example : Input 12345 will give us an output of 54321

namespace PurushLogics
{
    class Purush_ReverseInteger
    {
        static void Main()
        {
            //Reverse a Number  
            int intstr;
            string intreverse = "";
            int intLength = 0;
            int? intj = null;
            Console.WriteLine("Enter a Number"); // Entering "12345" has input will return "54321" as output

            intstr = int.Parse(Console.ReadLine());//Getting integer from Console  

            char[] inta = intstr.ToString().ToCharArray();


            intLength = inta.Length - 1;
            for (int c = intLength; c >= 0; c--)
            {
                intreverse = intreverse + inta[c].ToString();
                intj = int.Parse(intreverse);
            }

            Console.WriteLine("Reverse Number is \"{0}\"", intj);//Displaying the reverse integer  
            Console.ReadLine();

            //Reverse integer using Array.Reverse
            Array.Reverse(inta);
            foreach (char reverse in inta)
            {
                Console.Write(reverse);
            }
            Console.ReadLine();
        }
    }
}

Richard Kedang · Accepted Answer · 2019-11-11 04:42:04Z

0

static void Main(string[] args)
        {
            int[] numbers = new int[6];
            for (int i = 0; i < 6; i++)
            {
                Console.Write("Number {0} : ", i + 1);
                numbers[i] = Convert.ToInt32(Console.ReadLine());
            }
            Console.WriteLine();
            for (int i = 5; i >= 0; i--)
            {
                Console.Write("{0} ", numbers[i]);

            }

            Console.ReadLine();
        }

answered Nov 11, 2019 at 4:42

Richard Kedang

1

Comments

Hash_S · Accepted Answer · 2019-08-09 00:04:55Z

-1

   class Program
{
    static void Main(string[] args)
    {
        int[] array = new int[] { 1, 2, 3, 4, 5, 6,7};
        int temp = 0;
        for (int i = array.Length - 1; i >= (((array.Length - 1) % 2==0)? (((array.Length - 1) / 2)):((array.Length - 1) / 2)+1) ; i--)
        {
            temp = array[(array.Length - 1) - i];
            array[(array.Length - 1) - i] = array[i];
            array[i] = temp;
        }

        foreach (var p in array)
        {
            Console.WriteLine(p);
        }
        Console.ReadLine();
    }
}

answered Aug 9, 2019 at 0:04

Hash_S

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Comments

user11956714 · Accepted Answer · 2019-08-21 11:24:35Z

-1

int[] numbers=new int[]{1,2,3,4,5};
    int[] reverse=new int[numbers.Length];
    int j=numbers.Length-1;
    for(int i=0;i<numbers.Length;i++)
    {

        reverse[i]=numbers[j];
        Console.WriteLine(reverse[i]);
        j--;
    }

answered Aug 21, 2019 at 11:24

user11956714

1

1 Comment

Johan Over a year ago

Welcome to Stack Overflow! While this code snippet may be the solution, including an explanation really helps to improve the quality of your post. Remember that you are answering the question for readers in the future, and those people might not know the reasons for your code suggestion.

Rahul · Accepted Answer · 2021-09-15 14:49:17Z

-1

    public static int[] Test( params Int32[] nums)
    {
        int[] ar = new int[nums.Length];
        var count = 0;
        for (int i = nums.Length-1; i >= 0 ; i--)
        {
            ar[count] = nums[i];
            count++;
        }
        return ar;
    }

answered Sep 15, 2021 at 14:49

Rahul

1

1 Comment

zcoop98 Over a year ago

Welcome to Stack Overflow! While this code snippet may be the solution, including an explanation really helps to improve the quality of your post. Remember that you are answering the question for readers in the future, and those people might not know the reasons for your code suggestion.

Vignesh J · Accepted Answer · 2023-07-17 03:36:55Z

-1

This is Palindrom or not  string tmp=""; string values = "";Console.Write("Please Enter Number : "); string strnumber = Convert.ToString(Console.ReadLine());  tmp = strnumber; if (strnumber.Length > 0)  { foreach (var res in strnumber.Reverse())  { values += res; } }  if (values == strnumber)  { Console.WriteLine("Number is Palindrome."); }  else { Console.WriteLine("Number is not Palindrome")

edited Jul 17, 2023 at 3:36

answered Jul 17, 2023 at 3:31

Vignesh J

11 bronze badge

2 Comments

Community Over a year ago

Your answer could be improved with additional supporting information. Please edit to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers in the help center.

Chenmunka Over a year ago

This does not provide an answer to the question. Once you have sufficient reputation you will be able to comment on any post; instead, provide answers that don't require clarification from the asker. - From Review

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