c# 基础

freature of c#
　　Assembly Versioning
　　Properties and Events
　　Delegates and Events Management
　　Indexers
　　Conditional Compilation
　　Simple Multithreading
　　LINQ and Lambda Expressions

namespace

　　There is no package, but nested namespace instead.

namespace outer
{
namespace inner
{
    class Demo
    {
        // some code here
    }
}
}

value type

　　to get exact size of a type of variable, you can use sizeof method.

reference type

　　object type

　　　　the object type can be assigned values of any other types,
　　　　value type
　　　　reference type
　　　　or user-defined type

　　　　object obj;
　　　　obj = 100; // this is boxing

　　dynamic type
　　　　you can store any type of value in the dynamic data type variable.
　　　　type checking takes place at run-time.

　　　　dynamic <variable_name> = value;
　　　　dynamic d = 20;

　　　　the difference between dynamic type and object type is the time when type checking takes place.
　　　　former's type type checking takes place at run-time.
　　　　later's type type checking takes place at compile time.

　　string

　　　　The string type is an alias for the System.String class.
　　　　It is derived from object type.
　　　　There are two forms:
　　　　　　quoted
　　　　　　@quoted

pointer type
　　pointer in c# have the same capabilities as the pointers in c or c++.
　　we will discuss pointer types as unsafe codes.

lvalue: An expression that is an lvalue may appear as either the left-hand or right-hand side of an assignment.

rvalue: An expression that is an rvalue may appear on the right- but not left-hand side of an assignment.

array

double[] balance = new double[10];
for (int i = 0; i < 10; i++)
{
    balance[i] = i;
}
foreach (double d in balance)
{
    Console.WriteLine(d + "
");
}

structures in c#

struct Books
{
    public string title;
    public string author;
    public string subject;
    public int book_id;
};

class versus struct
　　*classes are reference types and structs are value types
　　structures do not support inheritance
　　structures cannot have default constructor

c# has preprocessor directives like in c or c++.

exception handling
　　try
　　catch
　　finally
　　throw

以上内容均来自 https://www.tutorialspoint.com/csharp/