static void Main() { int count1 = 0; int count2 = 0; Console.WriteLine("请输入字符串"); string str = Convert.ToString(Console.ReadLine()); char[] chars = str.ToCharArray(); foreach(char num in chars){ if(num>='A' && num<='Z'){ count1++; }else if(num>='a' && num<='z'){ count2++; } } Console.WriteLine("大写个数为:"+count1); Console.WriteLine("小写个数为:" + count2); Console.ReadKey(); }