Class-diagram.md

-Class diagram specs
+[Original mermaid js class diagram documentation](https://mermaid-js.github.io/mermaid/#/classDiagram)
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+
+> "In software engineering, a class diagram in the Unified Modeling Language (UML) is a type of static structure diagram that describes the structure of a system by showing the system's classes, their attributes, operations (or methods), and the relationships among objects." Wikipedia
+
+To create a class diagram call `Create` method of `ClassDiagram` class
+```c#
+var diagram = ClassDiagram.Create(Orientation.RightToLeft);
+```
+
+## Classes
+### Definition
+```c#
+var typeName = new TypeName("List", "int[]");
+var listOfIntArrays = diagram.AddClass(typeName, "My list annotation", "customCssClass");
+```
+### Properties
+Examples: define property `public abstract List<decimal> Foo { ... }`
+use this 
+```c#
+myClass.AddProperty(
+    "Foo",
+    new TypeName("List", "decimal"),
+    Visibility.Abstract | Visibility.Public
+);
+```
+### Functions
+Example: define method `private static decimal Average(decimal[] values)`
+```c#
+myClass.AddFunction(
+    "Average",
+    new TypeName("decimal", null),
+    Visibility.Static | Visibility.Private,
+    new FunctionArgument(
+        "values",
+        new TypeName("decimal[]", null)))
+```
+## Relations
+```c#
+diagram.Relation(
+    // related classes
+    firstClass,
+    secondClass,
+    
+    // first class relation
+    Relationship.Aggregation,
+    Cardinality.Many,
+    
+    // second class relation
+    Relationship.Composition,
+    Cardinality.ZeroToN,
+    
+    // relation link style and text
+    RelationLink.Solid,
+    "SomeLable");
+```
+
+## Interaction
+### Callbacks
+```c#
+myClass.SetCallback("alert", "CALLBACK TOOLTIP");
+```
+
+### Links
+```c#
+myClass.SetLink(new Uri("https://github.com"), "github toolTIP");
+```
+
+## Generate markdown syntax
+```c#
+string markdownSyntax = diagram.Render();
+```
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