static void Main(string[] args)
{
//浮点型， 由于计算机表达十进制小数时有误差，控制循环次数可能会有误差，但也不一定。为保险起见，能用整型，则用整型。
for (var i = 0.1; i <= 1.0001; i = i + 0.05)
{
Console.WriteLine(i);
}
#region 小数点默认类型double
var a = 3.24; //小数默认double类型
Console.WriteLine(a.GetType());
#endregion
#region long类型
Console.WriteLine(long.MaxValue); //9223372036854775807 19位 负号- 20位
Console.WriteLine(ulong.MaxValue); //18446744073709551615 20位
//Console.WriteLine(Convert.ToInt64(Math.Pow(2, 64))); //报错
Console.WriteLine(Convert.ToUInt64(Math.Pow(2, 63))); //9223372036854775808 19位
//Console.WriteLine(Convert.ToUInt64(Math.Pow(2, 64))); //报错
Console.WriteLine(Math.Pow(2, 64));//18446744073709551616 20位
ulong sum = Convert.ToUInt64(Math.Pow(2, 0));
for (int i = 1; i <= 63; i++)
{
sum = sum | Convert.ToUInt64(Math.Pow(2, i));
}
Console.WriteLine(sum); //18446744073709551615 一共64个
Console.WriteLine(18446744073709551615 & 2); //18446744073709551615 一共64个
#endregion
Test t = new Test();
t.x = 100;
object tt = t; //装箱
((Test)tt).test(300); //x还是100不变，为什么
Console.WriteLine(decimal.MinValue);
Console.WriteLine(default(List <string>) == null);
Console.WriteLine(new Student().Sta);
DervEmployee objDervEmployee = new DervEmployee();
objDervEmployee.EmpInfo();
Console.ReadKey();
}
//private const DateTime date = DateTime.Now;
static void Main(string[] args)
{
//浮点型， 由于计算机表达十进制小数时有误差，控制循环次数可能会有误差，但也不一定。为保险起见，能用整型，则用整型。
//for (var i = 0.1; i <= 1.0001; i = i + 0.05)
//{
// Console.WriteLine(i);
//}
#region 小数点默认类型double
var a = 3.24; //小数默认double类型
Console.WriteLine(a.GetType());
#endregion
#region long类型
Console.WriteLine(long.MaxValue);//9223372036854775807 19位 负号- 20位
Console.WriteLine(ulong.MaxValue);//18446744073709551615 20位
//Console.WriteLine(Convert.ToInt64(Math.Pow(2, 64))); //报错
Console.WriteLine(Convert.ToUInt64(Math.Pow(2, 63))); //9223372036854775808 19位
//Console.WriteLine(Convert.ToUInt64(Math.Pow(2, 64))); //报错
Console.WriteLine(Math.Pow(2, 64));//18446744073709551616 20位
//ulong sum = Convert.ToUInt64(Math.Pow(2, 0));
//for (int i = 1; i <= 63; i++)
//{
// sum= sum | Convert.ToUInt64(Math.Pow(2, i));
//}
//Console.WriteLine(sum); //18446744073709551615 一共64个
Console.WriteLine(18446744073709551615 & 2); //18446744073709551615 一共64个
#endregion
Test t = new Test();
t.x = 100;
object tt = t;//装箱
((Test)tt).test(300);//x还是100不变，为什么
Console.WriteLine(new Student().Sta);
DervEmployee objDervEmployee = new DervEmployee();
objDervEmployee.EmpInfo();
Student aaa = new Student();
Student bbb = new Student();
Console.WriteLine(Encoding.UTF8.GetBytes("666666")[0]);
Console.WriteLine(aaa == bbb);
Console.WriteLine(decimal.MinValue);
int? s = null;
Console.WriteLine(s.ToString());
string sss = null;
//Console.WriteLine(sss.ToString());
Console.WriteLine(3.3 > null);//始终为false
int? i = (int?)Status.X;
var list = new List<string>();
var dat = new List<string> { "1"};
list.AddRange(dat);
string str = "1234567";
var str1 = str.Substring(0, 2);
str1 = "21";
var str2 = str.Substring(2, 4);
Console.WriteLine(str1 + str2);
var pros = typeof(Student).GetProperties();
var fields= typeof(Student).GetFields();
var stu = new Student();
var typebool = typeof(bool);
var typebool2 = typeof(bool?);
var typeint2 = typeof(int?);
Console.WriteLine(typebool == typebool2);
Console.WriteLine(typebool2 == typeint2);
Console.WriteLine(-1> 0 & 1 > 0);
Console.WriteLine(float.Parse("3.1415926654"));
Console.WriteLine(Convert.ToInt64(null));
Console.WriteLine(21.02.ToString("#0.#####"));
List<int> nums = new List<int>();
for(int b = 0; b < 10000000; b++)
{
nums.Add(b);
}
var datetimes = nums.Select(x => new { Name = x, Time =DateTime.Now }).ToList();
Console.WriteLine(datetimes[0].Time);
Console.WriteLine(datetimes[9999999].Time);
Console.WriteLine(2 | 536870912);
Console.WriteLine(2 | 1073741824); //2的30次方
Console.WriteLine(2 | 2147483648);
Console.WriteLine(2 | 4294967296);
Console.WriteLine(2 | 4294967296);
Console.WriteLine(Math.Pow(2, 30));
long sum = 0;
for(int x = 0; x <= 30; x++)
{
sum = sum | Convert.ToInt64(Math.Pow(2, x));
}
Console.WriteLine(sum); //2147483647
Console.WriteLine(2 | 2147483647); //2147483647
Console.WriteLine(4 | 2147483647); //2147483647
Console.WriteLine(8 | 2147483647); //2147483647
Console.WriteLine(Convert.ToString(2147483647, 2));
Console.WriteLine(Convert.ToString(2147483647, 2).Length);
Console.WriteLine(Convert.ToString(2147483648, 2));
Console.WriteLine(Convert.ToString(2147483648, 2).Length);
Console.WriteLine(2 & 2147483647); //2147483647
Console.WriteLine(4 & 2147483647); //2147483647
Console.WriteLine(8 & 2147483647); //2147483647
Console.WriteLine(18446744073709551615 & 2); //18446744073709551615 一共64个
Console.WriteLine(Math.Pow(2, 53).ToString()); //9007199254740992
Console.WriteLine(Convert.ToString(9007199254740992, 2).Length);
Console.WriteLine(UInt32.MaxValue); //4294967295
Console.WriteLine(Int32.MaxValue); //2147483647
string url = "https://blog.csdn.net/vileman/article/details/84871000/sss.png";
//int m = url.LastIndexOf('.')+1;
//url = url.Substring(m);
var array = url.Split('.');
var type = array[array.Length - 1];
Console.WriteLine(type);
Console.WriteLine(float.Parse("31.237212"));
int? value = 0;
value++;
Console.WriteLine(value);
string code = "苏L0L937";
var flag=Regex.IsMatch(code, @"^(([京津沪渝冀豫云辽黑湘皖鲁新苏浙赣鄂桂甘晋蒙陕吉闽贵粤青藏川宁琼使领][A-Z](([0-9]{5}[DF])|([DF]([A-HJ-NP-Z0-9])[0-9]{4})))|([京津沪渝冀豫云辽黑湘皖鲁新苏浙赣鄂桂甘晋蒙陕吉闽贵粤青藏川宁琼使领][A-Z][A-HJ-NP-Z0-9]{4}[A-HJ-NP-Z0-9挂学警港澳使领]))$");
Console.WriteLine(Convert.ToInt64(Math.Pow(2, 0)));
//Console.WriteLine("".Substring(0, 2));
object num = 10;
long num2 = Convert.ToInt32(num);
Console.WriteLine(num2);
//Student sdfdf = new Student() { isT = null };
//Console.WriteLine(sdfdf.isT?.Value ?? false);
string str3 = "1.";
var strArray = str3.Split('.'); //两个 第二个空""
str3 = null ;
try
{
throw new H_Exception(str3);
}
//catch (H_Exception ex)
//{
// var aaaa = 1;
//}
catch (Exception ex) // null 的话 会引发"Exception of type 'Sino.SinoException' was thrown."
{
}
Student stu222 = new Student { Name = "小李子", ddd = DateTime.Now };
int number = 123;
Console.WriteLine(ToUrlParam(number));
Console.WriteLine(string.Join(',', new List<string>() { "1221" }));
Console.WriteLine("1232".Split(',')[0]);
Console.WriteLine("SJQKllrDin3Mz+L4P0ius1ARF3uqfNEA6PiUEf8pncQjbxCnBnDZ0oIGe5CEruws9h11KvDZPr4FW1K8fIzASjSe1VCrubTLcYQygkh3rgxgkhkiNVpUAq2f+uL03eXSoYHPh42aYNduNhYFS0HmGmJWXK/7NZ6OFi0u5xxpQg==".Length);
Console.WriteLine("VhV+LQGJJSdPz2UfzymHqKbAu8nYxxDPRnOZu+fEymaOm96E+3iB02u6ca25/gM/FeDo0O9HbJN3jKRmR/MVdlNbChW2dTafnLxQgFhFGf4S8rD8ImS3J1BnuBjhwIDE0L1eoRw4EKkO53Hpxb20A0GfW9f5VcL5TiAd1brdA/s=".Length);
bool abc = bool.Parse("true"); //可以转化 "1"不可以
Console.ReadKey();
}