哥德巴赫猜想即任意一個大於6的偶數,都可以寫成兩個素數的和。代碼如下:
using System;
using System.Collections.Generic;
using System.Text;
namespace ExGoldbachConjecture
{
class GoldbachConjecture
{
public bool IsPrimeNumber(int n)
{
bool b = true;
if (n == 1 || n == 2)
b = true;
else
{
int sqr = Convert.ToInt32(Math.Sqrt(n));
for (int i = sqr; i >= 2; i--)
{
if (n % i == 0)
{
b = false;
}
}
}
return b;
}
public bool goldbachConjecture(int n)
{
bool b = false;
if (n % 2 == 0 && n > 6)
{
for (int i = 1; i <= n / 2; i++)
{
bool b1 = IsPrimeNumber(i);//判斷i是否為素數
bool b2 = IsPrimeNumber(n - i);//判斷n-i是否為素數
if (b1 & b2)
{
Console.WriteLine("{0}={1}+{2}",n,i,n-i);
b = true;
}
}
}
return b;
}
static void Main(string[] args)
{
Console.WriteLine("輸入一個大於6的偶數");
int n = Convert.ToInt32(Console .ReadLine ());
GoldbachConjecture g=new GoldbachConjecture ();
bool b = g.goldbachConjecture(n);
if (b)
{
Console.WriteLine("{0}能寫成兩個素數的和。", n);
}
else
{
Console.WriteLine("猜想錯誤。");
}
}
}
}