C# for迴圈

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for(初始條件；比較；狀態改變  )

｛

迴圈體

｝

//列印100遍helloword

for(int i=0;i<100,i++)

{

console.writeline("helloword");

}

 

////求1-100的和
            int s = 0;
            for(int i=1;i<=100;i++)
            {
                s = s + i;
            }
            Console.WriteLine(s);
            Console.ReadLine();

 

//100以內所有與7相關的數和，奇數和，偶數和
            int s = 0;
            for (int i = 1; i <= 100; i++)
            {
                if ((i % 7 == 0) || (i % 10 == 7) || (i / 10 == 7))
                {
                    s = s + i;
                }
            }
            Console.WriteLine(s);
            Console.ReadLine();

 

//100以內的所有質數和

    int sum = 0;
            for (int i = 2; i <=100; i++)
            {
                int a = 0;
                for (int j = 1; j <=i; j++)
                {
                    if (i % j == 0)//如果i能被它本身和1以外的數整除，那麼他就不是質數
                    {
                       a++;
                    }
                }
                if (a == 2)  //能被整除的數只有兩個，即為質數
                {
                    sum = sum + i;
                    Console.Write(i + "\t");
                }
            }
            Console.Write("和"+sum);
            Console.ReadLine();

 

 //列印☆，排列成圖形

//右上
            for (int m = 1; m < 10; m++)
            {
                for (int n = 1; n <= m; n++)
                {
                    Console.Write("☆");
                }
                Console.Write("\n");
            }

 ////右下
            for (int m = 10; m > 1; m--)
            {
                for (int n = 1; n < m; n++)
                {
                    Console.Write("☆");
                }
                Console.Write("\n");
            }

////左下
            for (int m = 1; m < 10; m++)
            {
                for (int n = 1; n < m; n++)
                {
                    Console.Write("  ");
                }
                for (int l = 10; l > m; l--)
                {
                   Console.Write("☆");
                }
                Console.Write("\n");
            }

 ////左上
            for (int m = 1; m < 10; m++)
            {
                for (int n = 9; n >m; n--)
                {
                    Console.Write("  ");
                }
                for (int l = 1; l <= m;l++ )
                {
                   Console.Write("☆");
                }
            Console.Write("\n");
            }   

//上半部分
            for (int m = 1; m < 10; m++)
            {
                for (int n = 9; n > m; n--)
                {
                    Console.Write("  ");
                }
                for (int l = 1; l <= (2 * m - 1); l++)
                {
                    Console.Write("☆");
                }
                Console.Write("\n");
            }
 ////下半部分
            for (int m = 1; m < 9; m++)
            {
                for (int l = 1; l <= m; l++)
                {
                    Console.Write("  ");
                }
                for (int n = 1; n <= (2 * (9 - m) - 1); n++)
                {
                    Console.Write("☆");
                }
                Console.Write("\n");
            }  //一對幼兔一個月後長成小兔，再過一個月長成成兔並生下一對小兔，兩年後有多少對兔子？關係如 int a = 1, b = 0, c = 0;
            for (int i = 2; i <= 24; i++)
            {
                if (i == 1)
                {
                    c = 0;
                    b = 0;
                    a = 1;
                }
                else
                {
                    c = c + b;
                    b = a;
                    a = c;
                }
                Console.WriteLine("第{0}個月,成兔數量:{1}小兔數量{2}:幼兔數量{3}", i, c, b, a);
                Console.ReadLine();
            }
            Console.WriteLine("總數量為" + (c + a + b));
            Console.ReadLine();  //窮舉問題：鉛筆一支2元，筆盒5元，檔案夾10元，彩筆5元，買正好100塊的文具，每種至少買一種，列舉出所有方法for (int qianbi = 1; qianbi <= 50; qianbi++)
            {
                for (int he = 1; he <= 20; he++)
                {
                    for (int wenjianjia = 1; wenjianjia <= 10; wenjianjia++)
                    {
                        for (int caibi = 1; caibi <= 7; caibi++)
                        {
                            int a = qianbi * 2 + he * 5 + wenjianjia * 10 + caibi * 15;
                            if (a == 100)
                            {
                                Console.WriteLine("鉛筆買{0}只,盒買{1}個,檔案夾買{2}個,彩筆買{3}支", qianbi, he, wenjianjia, caibi);
                            }
                        }
                    }
                }
               
            }
            Console.ReadLine();

C# for迴圈