What is Prime Number ?
A number that is divisible only by itself and 1 (e.g. 2, 3, 5, 7, 11).
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
//Prime Number : A number that is divisible only by itself and 1 (e.g. 2, 3, 5, 7, 11).
namespace PrimeNumber
{
class Program
{
static void Main(string[] args)
{
int number, primeNumber;
Console.Write("\n\nInput any positive number : ");
number = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("\n\n Recursion : Check a number is prime number or not :");
Console.WriteLine("--------------------------------------------------------");
primeNumber = IsPrime(number, number / 2);
if (primeNumber == 1)
Console.Write("\n\nThe number {0} is a prime number. \n\n", number);
else
Console.WriteLine("\n\nThe number {0} is not a prime number. \n\n", number);
Console.WriteLine("--------------------------------------------------------");
Console.WriteLine("\n\n Non-Recursion : Check a number is prime number or not :");
Console.WriteLine("--------------------------------------------------------");
//Without Recursion
int i, flag = 0;
for (i = 2; i <= number / 2; ++i)
{
if (number % i == 0)
{
flag = 1;
break;
}
}
if (flag == 0)
Console.Write("\n\nThe number {0} is a prime number. \n\n", number);
else
Console.WriteLine("\n\nThe number {0} is not a prime number. \n\n", number);
Console.WriteLine("--------------------------------------------------------");
Console.ReadKey();
}
//Using Recursion
static int IsPrime(int number, int i)
{
if (i == 1)
{
return 1;
}
else
{
if (number % i == 0)
return 0;
else
return IsPrime(number, i - 1);//calling the function IsPrime itself recursively
}
}
}
}
- using System;
- using System.Collections.Generic;
- using System.Linq;
- using System.Text;
- using System.Threading.Tasks;
- //Prime Number : A number that is divisible only by itself and 1 (e.g. 2, 3, 5, 7, 11).
- namespace PrimeNumber
- {
- class Program
- {
- static void Main(string[] args)
- {
- int number, primeNumber;
- Console.Write("\n\nInput any positive number : ");
- number = Convert.ToInt32(Console.ReadLine());
- Console.WriteLine("\n\n Recursion : Check a number is prime number or not :");
- Console.WriteLine("--------------------------------------------------------");
- primeNumber = IsPrime(number, number / 2);
- if (primeNumber == 1)
- Console.Write("\n\nThe number {0} is a prime number. \n\n", number);
- else
- Console.WriteLine("\n\nThe number {0} is not a prime number. \n\n", number);
- Console.WriteLine("--------------------------------------------------------");
- Console.WriteLine("\n\n Non-Recursion : Check a number is prime number or not :");
- Console.WriteLine("--------------------------------------------------------");
- //Without Recursion
- int i, flag = 0;
- for (i = 2; i <= number / 2; ++i)
- {
- if (number % i == 0)
- {
- flag = 1;
- break;
- }
- }
- if (flag == 0)
- Console.Write("\n\nThe number {0} is a prime number. \n\n", number);
- else
- Console.WriteLine("\n\nThe number {0} is not a prime number. \n\n", number);
- Console.WriteLine("--------------------------------------------------------");
- Console.ReadKey();
- }
- //Using Recursion
- static int IsPrime(int number, int i)
- {
- if (i == 1)
- {
- return 1;
- }
- else
- {
- if (number % i == 0)
- return 0;
- else
- return IsPrime(number, i - 1);//calling the function IsPrime itself recursively
- }
- }
- }
- }
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
//Prime Number : A number that is divisible only by itself and 1 (e.g. 2, 3, 5, 7, 11).
namespace PrimeNumber
{
class Program
{
static void Main(string[] args)
{
int number, primeNumber;
Console.Write("\n\nInput any positive number : ");
number = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("\n\n Recursion : Check a number is prime number or not :");
Console.WriteLine("--------------------------------------------------------");
primeNumber = IsPrime(number, number / 2);
if (primeNumber == 1)
Console.Write("\n\nThe number {0} is a prime number. \n\n", number);
else
Console.WriteLine("\n\nThe number {0} is not a prime number. \n\n", number);
Console.WriteLine("--------------------------------------------------------");
Console.WriteLine("\n\n Non-Recursion : Check a number is prime number or not :");
Console.WriteLine("--------------------------------------------------------");
//Without Recursion
int i, flag = 0;
for (i = 2; i <= number / 2; ++i)
{
if (number % i == 0)
{
flag = 1;
break;
}
}
if (flag == 0)
Console.Write("\n\nThe number {0} is a prime number. \n\n", number);
else
Console.WriteLine("\n\nThe number {0} is not a prime number. \n\n", number);
Console.WriteLine("--------------------------------------------------------");
Console.ReadKey();
}
//Using Recursion
static int IsPrime(int number, int i)
{
if (i == 1)
{
return 1;
}
else
{
if (number % i == 0)
return 0;
else
return IsPrime(number, i - 1);//calling the function IsPrime itself recursively
}
}
}
}
You can also download the code from our GitHub.
Happy Coding.