C#基础练习

  string s1 = "";
            Console.Write("请输入一个字符串：");
            s1 = Console.ReadLine();

            
            for (int i = 0; i < s1.Length; i++)
            {
                
                if ((int)s1[i] >= 97 && (int)s1[i] <= 119)
                {
                    int b = (int)s1[i] + 3;
                    Console.Write(" "+(char)b);
                }

                else if((int)s1[i] >=120 && (int)s1[i]<=122)
                {
                    int b = (int)s1[i] - 23;
                    Console.Write(" "+(char)b);

                }
                else if((int)s1[i] >= 65 && (int)s1[i]<=87)
                {
                    int b = (int)s1[i] + 3;
                    Console.Write(" " + (char)b);
                }
                else if ((int)s1[i] >= 88 && (int)s1[i] <= 90)
                {
                    int b = (int)s1[i] - 23;
                    Console.Write(" " + (char)b);
                }

对输入的字符进行转化