Editing Common Intermediate Language (section)

===Object-oriented concepts===
CIL is designed to be object-oriented. One may create objects, call methods, and use other types of members, such as fields.

Every [[Method (programming)|method]] needs (with some exceptions) to reside in a class. So does this static method:
<syntaxhighlight lang="csharp">
.class public Foo {
    .method public static int32 Add(int32, int32) cil managed {
        .maxstack 2
        ldarg.0 // load the first argument;
        ldarg.1 // load the second argument;
        add     // add them;
        ret     // return the result;
    }
}
</syntaxhighlight>

The method Add does not require any instance of Foo to be declared because it is declared as static, and it may then be used like this in C#:
<syntaxhighlight lang="csharp">
int r = Foo.Add(2, 3);    // 5
</syntaxhighlight>

In CIL it would look like this:
<syntaxhighlight lang="csharp">
ldc.i4.2
ldc.i4.3
call int32 Foo::Add(int32, int32)
stloc.0
</syntaxhighlight>

====Instance classes====
An instance class contains at least one [[Constructor (object-oriented programming)|constructor]] and some [[Instance (computer science)|instance]] members. The following class has a set of methods representing actions of a Car-object.
<syntaxhighlight lang="csharp">
.class public Car {
    .method public specialname rtspecialname instance void .ctor(int32, int32) cil managed {
        /* Constructor */
    }

    .method public void Move(int32) cil managed { /* Omitting implementation */ }
    .method public void TurnRight() cil managed { /* Omitting implementation */ }
    .method public void TurnLeft() cil managed { /* Omitting implementation */ }
    .method public void Brake() cil managed { /* Omitting implementation */ }
}
</syntaxhighlight>

====Creating objects====
In C# class instances are created like this:
<syntaxhighlight lang="csharp">
Car myCar = new Car(1, 4); 
Car yourCar = new Car(1, 3); 
</syntaxhighlight>

And those statements are roughly the same as these instructions in CIL:
<syntaxhighlight lang="csharp">
ldc.i4.1
ldc.i4.4
newobj instance void Car::.ctor(int, int)
stloc.0    // myCar = new Car(1, 4);
ldc.i4.1
ldc.i4.3
newobj instance void Car::.ctor(int, int)
stloc.1    // yourCar = new Car(1, 3);
</syntaxhighlight>

====Invoking instance methods====
Instance methods are invoked in C# as the one that follows:
<syntaxhighlight lang="csharp">
myCar.Move(3);
</syntaxhighlight>

As invoked in CIL:
<syntaxhighlight lang="csharp">
ldloc.0    // Load the object "myCar" on the stack
ldc.i4.3
call instance void Car::Move(int32)
</syntaxhighlight>