# Java Program to Reverse a Given Number Without Using Recursion

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This is the Java Program to Reverse a Given Number Without Using Recursion.

Problem Description

Write a Java Program to Reverse a Given Number Without Using Recursion.

Problem Solution

Using a loop, extract the last digit of the number and add it at the end of the reverse formed till now.
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Program/Source Code

Here is the source code of the Java Program to Reverse a Given Number Without Using Recursion. The program is successfully compiled and tested using IDE IntelliJ Idea in Windows 7. The program output is also shown below.

1. ` `
2. `//Java Program to Reverse a Given Number Without Using Recursion`
3. ` `
4. `import java.io.BufferedReader;`
5. `import java.io.InputStreamReader;`
6. ` `
7. `public class ReverseNumber {`
8. `    // Function to reverse the number without using recursion`
9. `    public static void main(String[] args) {`
10. `        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));`
11. `        int n;`
12. `        try {`
13. `            System.out.println("Enter a number");`
14. `            n = Integer.parseInt(br.readLine());`
15. `        } catch (Exception e) {`
16. `            System.out.println("An error occurred");`
17. `            return;`
18. `        }`
19. `        int rev,i,s;`
20. `        rev = 0;`
21. `        for(i=n; i!=0; i/=10){`
22. `            rev= rev*10+(i%10);`
23. `        }`
24. `        System.out.println("The reverse is " + rev);`
25. `    }`
26. `}`
Program Explanation

1. In function main(), firstly the number is taken as input.
2. Then, the loop for(i=n; i!=0; i/=10), runs until the each digit is extracted, in the reverse order.
3. The statement rev= rev*10+(i%10); adds the digit obtained to the reverse.

Time Complexity: O(1).

Runtime Test Cases
```
Case 1 (Simple Test Case):

Enter a number
214224
The reverse is 422412```

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