{"id":10037,"date":"2022-09-28T10:18:00","date_gmt":"2022-09-28T10:18:00","guid":{"rendered":"https:\/\/www.prepbytes.com\/blog\/?p=10037"},"modified":"2023-07-24T07:34:37","modified_gmt":"2023-07-24T07:34:37","slug":"reverse-a-number-using-stack","status":"publish","type":"post","link":"https:\/\/prepbytes.com\/blog\/reverse-a-number-using-stack\/","title":{"rendered":"Reverse a Number using Stack"},"content":{"rendered":"

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A stack is a type of linear data structure that follows a specific order for performing operations. The sequence can either be Last In First Out (LIFO) or First In Last Out (FILO). Let\u2019s discuss the problem statement – Given an integer, your task is to use a Stack data structure to reverse its digits and return the resulting integer with the digits reversed.<\/p>\n

Example<\/h3>\n

If the number 123 is given to you as the input, the output will be 321. It is compulsory to use a Stack to reverse the number.<\/p>\n

Approach on How to Reverse a number using Stack Data Structure<\/h3>\n

Let’s take the number 12345 as an example. To extract each digit of this number and insert it into the stack, we calculate the remainder obtained by dividing the number by 10. This remainder represents the last digit, and the leftover number is the result after removing the last digit.<\/p>\n

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So, we have to do this till the number is greater than 0. The following images show how we are extracting the digits from the number and inserting them into the Stack.<\/p>\n

![]()<\/p>\n

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So, now when the number has become 0, we will stop our procedure. So, we have the digits of the number in the Stack. Now, we have to create an integer that will be the reverse of the input. So, for that, let us take an integer \u201creverse\u201d and initialize it to 0 and a variable \u201cpower\u201d initialized to 1 as shown below.<\/p>\n

\"\"<\/p>\n

Now, we will pop a digit from the stack, and add it to our reverse by multiplying it with power. The variable power will be multiplied by 10 in every iteration. For instance, let us pop 1 from the stack first.<\/p>\n

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Now, in the next iteration, the value of reverse will be 1 and the value of power will be 10.<\/p>\n

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So, let us extract the digit again and add it to reverse by multiplying it with power.<\/p>\n

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So, the reverse will now be 21 and the power will be 100.<\/p>\n

\"\"<\/p>\n

So, we again pop from the Stack, and this time we get the digit 3. We again, add the digit to the reverse by multiplying it with power.<\/p>\n

\"\"<\/p>\n

So, similarly, we will perform these operations till the Stack is empty. The remaining 2 iterations are shown below.<\/p>\n

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After all these iterations, we have got the reversed number. So, now that we have understood the procedure, let us write the code for the same.<\/p>\n

Code Implementation<\/h3>\n\t\t\t\t\t\t