用C#编写一个程序以接受用户的数字并显示从0到用户输入数之间的所有质数。
谢谢了。。。。。。。。

用C#编写一个程序以接受用户的数字并显示从0到用户输入数之间的所有质数。
谢谢了。。。。。。。。

思路是从2到用户输入的数做个循环,依次检查是否质数

如何检查呢?做个嵌套循环,从2开始依次作除数,能被整除就跳过,继续

for (int j = 2; j <= m; j++)
            {
                bool ff = true;
                k = Convert.ToInt32(Math.Sqrt(j));
                for (int i = 2; i <= k; i++)
                {
                    if (j % i == 0)
                    {
                        ff = false;
                        break;
                    }
                }
                if (ff == true)
                { Console.WriteLine(j); }

质数的意思就是这个数只能被1和它本身整除，这个数就叫做质数。
根据这个概念，就可以写了。

谢谢 大家的帮忙

using System;
class Num
{
    int num;
    int i=2;
    public void Accept()
    {
        Console.WriteLine("please enter a number !");
        num=Convert.ToInt32(Console.ReadLine());
    }
    public void Display()
    {
        Console.WriteLine("the number {0} is you enter !",num);
        Console.WriteLine("the prime number from 0 to {0}!",num);
        Console.WriteLine("please enter which you want to contiue !");
        Console.ReadLine();
        for (;i<=num;i++)
                {
                    bool l=true;
                    int m =Convert.ToInt32(Math.Sqrt(i));
                    for (int j=2;j<=m;j++)
                    {
                            if (i%j==0)
                            {
                                l=false;                    
                                break;
                            }
                        }
                    if (l==true)
                    {
                            Console.WriteLine(i);
                    }
        }
    }
    public static void Main(string[] args)
    {
        Num A=new Num();
        A.Accept();
        A.Display();
    }
}

呵呵~让我有想用迭代器的冲动。。。。。。貌似C#入门经典里面有这么个例子

迭代器 ,能解释下吗

namespace 质数
{
    /// <summary>
    /// 输入一个整数,返回小于该整数的所有质数
    /// </summary>
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("请输入一个正整数:");
            int n = int.Parse(Console.ReadLine());
            int[] zs = new int[n + 1];
            for (int i = 2; i <= n; ++i)        //数组初始化
                zs[i] = 0;
            for (int i = 2; i <= n; ++i)        //从2到n循环,检测其中质数
            {
                for (int j = 2; j < i && j*j<n; ++j)    //如果能被小于它自己的数整除(取n的平方根的下界就行)的数不是质数,将数组中此元素置1
                    if (i % j == 0)
                        zs[i] = 1;
            }
            for (int i = 2; i <= n; ++i)
                if (zs[i] == 0)
                    Console.WriteLine(i);
        }
    }
}