C#, finding the largest prime factor of a number
- by Juan
Hello! I am new at programming and I am practicing my C# programming skills. My application is meant to find the largest prime factor of a number entered by the user. But my application is not returning the right answer and I dont really know where the problem is. Can you please help me?
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Calcular máximo factor primo de n. De 60 es 5.");
Console.Write("Escriba un numero: ");
long num = Convert.ToInt64(Console.ReadLine());
long mfp = maxfactor(num);
Console.WriteLine("El maximo factor primo es: " + num);
Console.Read();
}
static private long maxfactor (long n)
{
long m=1 ;
bool en= false;
for (long k = n / 2; !en && k > 1; k--)
{
if (n % k == 0 && primo(k))
{
m = k;
en = true;
}
}
return m;
}
static private bool primo(long x)
{
bool sp = true;
for (long i = 2; i <= x / 2; i++)
{
if (x % i == 0)
sp = false;
}
return sp;
}
}
}
