回顾昨天的笔记

题目1

            Console.WriteLine("请输入层数n");
            int n = Convert.ToInt32(Console.ReadLine());
            for (int i = 1; i <= n; i++) { 
                for(int j=1; j<=i;j++)
                {
                    Console.Write("*");
                }
                Console.WriteLine();
            }
           

题目二

           Console.WriteLine("请输入层数n");
            int n = Convert.ToInt32(Console.ReadLine());
            for (int i = 1; i <= n; i++) 
            {
                for (int k = 1; k <= n - i; k++)
                {
                    Console.Write(" ");
                }
                for (int j = 1; j <= 2*i-1; j++)
                {
                    Console.Write("*");
                }
                Console.WriteLine();
            }

题目三

            Console.WriteLine("请输入层数n");
            int n = Convert.ToInt32(Console.ReadLine());
            for (int i = 1; i <= n; i++)
            {
                for (int k = 1; k <= n - i; k++)
                {
                    Console.Write(" ");
                }
                for (int j = 1; j <= 2 * i - 1; j++)
                {
                    Console.Write("*");
                }
                Console.WriteLine();
            }
            for(int i = 1; i <= n-1; i++)
            {
                for (int k = 1; k <=i; k++)
                {
                    Console.Write(" ");
                }
                for (int j = 1; j <= 2 * (n-i) - 1; j++)
                {
                    Console.Write("*");
                }
                Console.WriteLine();

            }

练习四 乘法口诀

          for (int i = 1; i <=9; i++)
            {
                for (int j = 1; j <= i; j++)
                {
                    int sum = i * j;
                    Console.Write("{0}*{1}={2}", i, j, sum);
                    Console.Write(" ");
                }
                Console.WriteLine();
            }

            for (int i = 9; i >=1; i--)
            {
                for (int j = 1; j <= i; j++)
                {
                    int sum = i * j;
                    Console.Write("{0}*{1}={2}",i,j,sum);
                    Console.Write(" ");
                }
                Console.WriteLine();
            }

题目五

有100元去购买公鸡母鸡小鸡，公鸡的价钱是3元，母鸡价钱是5元，小鸡价钱是2元，可以购买多少只公鸡母鸡小鸡，把所以的情况输出，要求必须有公鸡母鸡小鸡。

            for (int i = 1; i <= 100/3; i++)
            {
                for (int j = 1; j <= 100/5; j++)
                {
                    for (int k = 1; k <= 100 / 2; k++)
                    {
                        if (i * 3 + j * 5 + k * 2 == 100 && i+j+k<=100)
                        {
                            Console.WriteLine("公鸡有{0},母鸡有{1},小鸡有{2}",i,j,k);
                        }

                    }
                }

            }

练习1输入两个整数mun1和mun2，输出这两个正整数mun1和mun2的最大公约数

           Console.WriteLine("请输入正整数mun1");
            int a = Convert.ToInt32(Console.ReadLine());
            Console.WriteLine("请输入正整数mun2");
            int b = Convert.ToInt32(Console.ReadLine());
            if (a > b)
            {
                for (int i = b; i > 0; i--)
                {
                    if (a % i == 0 && b % i == 0)
                    {
                        Console.WriteLine("最大公约数是{0}", i);
                        break;
                    }
                        
                }

            }
            else
            {
                for (int i = a; i > 0; i--)
                {
                    if (a % i == 0 && b % i == 0)
                    {
                        Console.WriteLine("最大公约数是{0}", i);
                        break;
                    }
                       
                }
            }

创建一个随机数 用到的是Random类 会生成一个Random对象 对象中会有一个方法next（a,b） 表示取a到b-1的整数 不包括b

例如

           Random c = new Random();//Random数据
            int d = c.Next(1, 9);
            Console.WriteLine(d);
   

练习2:由系统生成一个随机数100-1，要是猜对了就退出循环，猜大了就提示猜大，猜小了就提示猜小，没有猜中的话就一直猜

            Random c = new Random();
            int d = c.Next(1, 100);
            while (true)
            {
                Console.WriteLine("请输入你要猜的数字");
                int n = Convert.ToInt32(Console.ReadLine());
                if (d < n)
                {
                    Console.WriteLine("猜大了");
                }
                else if (d > n)
                {
                    Console.WriteLine("猜小了");
                }
                else
                {
                    Console.WriteLine("恭喜你猜对了");
                    break;
                }
            }