query for c# program

Bhagwan Aswal

11y1.1kVisual Basic .NET

program in C# to find number enterd by user is prime or not using function.

4 Replies

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Bhagwan Aswal11y ago
thank you i m thankful to you.
Vikram Agrawal11y ago
Hey Bhagwan,
Try this one also

private static bool IsPrime(int num)
{
if(num<=1)
return false;
if(num%2==0)
return false;
for(int i=2;i<=num/2;i++)
{
if(num%i==0)
return false;
}

return true;
}

call this method where ever you want like:

static void Main()
{
int num;
Console.Write("Enter a Number : ");
num=Convert.ToInt32(Console.ReadLine());
if(IsPrime(num))
{
Console.WriteLine(num + " is a Prime Number.");
}
else
{
Console.WriteLine(num + " is not a Prime Number.");
}
}
Vulpes11y ago
Try this:

using System;

class Program
{
static void Main()
{
int n ;

while(true)
{
Console.Write("Enter a positive integer or 0 to finish : ");
int.TryParse(Console.ReadLine(), out n);
if (n == 0) return;
if(IsPrime(n))
{
Console.WriteLine("{0} is prime", n);
}
else
{
Console.WriteLine("{0} is not prime", n);
}

Console.WriteLine();
}
}

static bool IsPrime(int x)
{
if (x <= 1) return false;

for (int i = 2; i <= x / 2; i++)
{
if ((x % i) == 0)
{
return false;
}
}

return true;
}
}
Manish Kumar Choudhary11y ago
Hi Bhagwan Aswal,
Do it by using following lines of code.
Function
private static int CheckPrime(int number)
       {
            int i;
            for (i = 2; i <= number - 1; i++)
            {
                if (number % i == 0)
                {
                    return 0;
                }
            }
            if (i == number)
            {
                return 1;
            }
            return 0;
        }
Call :
            Console.WriteLine("Enter a number");
            int number = Convert.ToInt32(Console.ReadLine());
            int result = CheckPrime(number);
            if (result == 0)
            {
                Console.WriteLine("{0} is not a prime number", number);
            }
            else
            {
                 Console.WriteLine("{0} is a prime number", number);
            }
            Console.Read();