方法的调用练习

练习一：<br>class Program
   {
        
       //虽然是公有字段，但方法中失效。
       public static int _number = 10;
 
 
       static void Main(string[] args)
       {
            
           int a = 3;
           int res = Test(a);
           Console.WriteLine(res);
          //  Console.WriteLine(_number); //输出：10
           Console.ReadKey();
       }
       public static int Test(int a)
       {
           a = a + 5;
           return a;
         //   Console.WriteLine(_number); //无输出
       }
 
 
       public static void TestTwo()
       {
         // Console.WriteLine(_number); //无输出
       }
   }    

练习二：

class Program
    {
        static void Main(string[] args)
        {
            //举例:写一个方法,判断一个年份是否是润年.
 
            bool b = IsRun(2001);
            Console.WriteLine(b);
            Console.ReadKey();
 
        }
        /// <summary>
        /// 判断给定的年份是否是闰年
        /// </summary>
        /// <param name="year">要判断的年份</param>
        /// <returns>是否是闰年</returns>
        public static bool IsRun(int year)
        {
            bool b = (year % 400 == 0) || (year % 4 == 0 && year % 100 != 0);
            return b;
        }
 
 
    }

练习三

class Program
    {
        public static void Main(string[] args)
        {
            //比较两个数字的大小 返回最大的
            //int a1 = 10;
            //int a2 = 20;
            int max = GetMax(10, 20);//实参
            Console.WriteLine(max);
            Console.ReadKey();
        }
 
 
        /// <summary>
        /// 计算两个整数之间的最大值 并且返回最大值
        /// </summary>
        /// <param name="n1">第一个数</param>
        /// <param name="n2">第二个数</param>
        /// <returns>返回的最大值</returns>
        public static int GetMax(int n1, int n2)//形参
        {
            int max = n1 > n2 ? n1 : n2;//如果 n1 > n2成立，则输出n1，否则输出n2
 
            return max;
        }
    }

练习四

class Program
   {
       static void Main(string[] args)
       {
           //1 读取输入的整数
           //多次调用(如果用户输入的是数字,则返回,否则提示用户重新输入)
 
           Console.WriteLine("请输入一个数字");
           string input = Console.ReadLine();
           int number = GetNumber(input);
           Console.WriteLine(number);
           Console.ReadKey();
       }
 
       /// <summary>
       /// 这个方法需要判断用户的输入是否是数字
       /// 如果是数字，则返回
       /// 如果不是数字，提示用户重新输入
       /// </summary>
       public static int GetNumber(string s)
       {
           while (true)
           {
               try
               {
                   int number = Convert.ToInt32(s);
                   return number;
               }
               catch
               {
                   Console.WriteLine("请重新输入");
                   s = Console.ReadLine();
               }
           }
       }
 
 
   }

练习五

class Program
   {
       static void Main(string[] args)
       {
        
           //只能让用户输入yes或者no，只要不是，就重新输入
 
 
           //Console.WriteLine("请输入yes或者no");
           //string str = Console.ReadLine();
           //string result = IsYerOrNo(str);
           //Console.WriteLine(result);
           //Console.ReadKey();
 
           //4计算输入数组的和：int Sum(int[] values)
           int[] nums = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
           int sum = GetSum(nums);
           Console.WriteLine(sum);
           Console.ReadKey();
       }
 
       /// <summary>
       /// 计算一个整数类型数组的总和
       /// </summary>
       /// <param name="nums">要求总和的数组</param>
       /// <returns>返回这个数组的总和</returns>
       public static int GetSum(int[] nums)
       {
           int sum = 0;
           for (int i = 0; i < nums.Length; i++)
           {
               sum += nums[i];
           }
           return sum;
       }
 
 
 
       /// <summary>
       /// 限定用户只能输入yes或者no 并且返回
       /// </summary>
       /// <param name="input">用户的输入</param>
       /// <returns>返回yes或者no</returns>
       public static string IsYerOrNo(string input)
       {
           while (true)
           {
               if (input == "yes" || input == "no")
               {
                   return input;
               }
               else
               {
                   Console.WriteLine("只能输入yes或者no，请重新输入");
                   input = Console.ReadLine();
               }
           }
       }
   }