实现效果：
知识运用：
（给定的占位符以冒号为标记 将这些字符作为后缀）
实现代码：
static void Main(string[] args)
{
Console.WriteLine("The Value 99999 in various formats:");
Console.WriteLine("C Format: {0:C}",99999);
Console.WriteLine("D9 Format: {0:D9}",99999);
Console.WriteLine("E Format: {0:E}", 99999);
Console.WriteLine("F9 Format: {0:F9}",99999);
Console.WriteLine("N Format: {0:N}",99999);
Console.WriteLine("X Format: {0:X}",99999);
Console.WriteLine("x Format: {0:x}",99999);
}
