Added article on implicit types (#31234)

guide/english/csharp/implicit-types/index.md

@@ -0,0 +1,28 @@
+---
+title: Implicit Types
+---
+
+# Implicit Types
+
+C# supports the use of ***implicit types***, which means that rather than declaring a variable with an explicit type, such as `string` or `int`, you can instead use the `var` keyword to prompt the compiler to determine the variable's type.
+
+As an example, the following two lines of code are functionally equivalent:
+
+```
+int i = 5;
+var j = 5;
+```
+
+Please note that this does not mean that the type of the variable is loosely-typed; using the example above, if a subsequent line of code were to try to assign a string value to `j` an exception will be thrown.
+
+The use of `var` is mainly as a convenience, but there are some situations that you will need to use them; for example, if you want to initialise a variable with an anonymous type, the only way to do this will be to declare it as a `var`.
+
+### Readability
+
+Be aware that while implicit types can be useful, they can also potentially make it harder for other developers to understand your code.  Consider the following line:
+
+```
+var thing = MyFunction();
+```
+
+It is impossible to determine the type of `thing` at a glance, instead the reader would instead have to look at the implementation of `MyFunction()` to see what it is returning.