---
title: "Write a program to find the largest prime number within a given range."  
description: "Write a program to find the largest prime number within a given range."  
author: "Utpal Vishwas"  
published: 2023-06-14  
updated: 2023-06-15  
canonical: https://www.mindstick.com/forum/158743/write-a-program-to-find-the-largest-prime-number-within-a-given-range  
category: "c#"  
tags: ["c#", "programs"]  
reading_time: 2 minutes  

---

# Write a program to find the largest prime number within a given range.

Write a [program](https://www.mindstick.com/blog/12337/scaling-up-your-mentorship-program) to find the [largest prime](https://www.mindstick.com/forum/158829/create-a-rust-program-to-find-the-largest-prime-factor-of-a-given-number) number within a given range.

## Replies

### Reply by Aryan Kumar

Sure, here is a C# program to find the largest prime number within a given range:

C#

```plaintext
using System;

public class LargestPrimeNumber {

    public static int LargestPrimeNumber(int start, int end) {

        // Initialize the largest prime number to 0
        int largestPrimeNumber = 0;

        // Iterate through all numbers from start to end
        for (int i = start; i <= end; i++) {

            // Check if the current number is prime
            bool isPrime = true;
            for (int j = 2; j * j <= i; j++) {
                if (i % j == 0) {
                    isPrime = false;
                    break;
                }
            }

            // If the current number is prime, update the largest prime number
            if (isPrime && i > largestPrimeNumber) {
                largestPrimeNumber = i;
            }
        }

        // Return the largest prime number
        return largestPrimeNumber;
    }

    public static void Main() {

        // Get the start and end of the range from the user
        Console.WriteLine("Enter the start of the range: ");
        int start = Convert.ToInt32(Console.ReadLine());
        Console.WriteLine("Enter the end of the range: ");
        int end = Convert.ToInt32(Console.ReadLine());

        // Find the largest prime number in the given range
        int largestPrimeNumber = LargestPrimeNumber(start, end);

        // Print the largest prime number
        Console.WriteLine("The largest prime number in the given range is: " + largestPrimeNumber);
    }
}
```

This program will first get the start and end of the range from the user. It will then call the LargestPrimeNumber method to find the largest prime number in the given range. The program will then print the largest prime number.

Here is an example of how to run the program:

Code snippet

```plaintext
C#> LargestPrimeNumber.exe
Enter the start of the range: 2
Enter the end of the range: 10
The largest prime number in the given range is: 7
```


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Original Source: https://www.mindstick.com/forum/158743/write-a-program-to-find-the-largest-prime-number-within-a-given-range

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