Pre- & Post Increment in C#

Question

I am a little confused about how the C# compiler handles pre- and post increments and decrements.

When I code the following:

int x = 4;
x = x++ + ++x         


        

Answer 1

Lets have a look at the IL that gets generated from that statement

IL_0002:  ldloc.0     

Loads the value of x onto the stack. Stack => (4)

IL_0003:  dup         

Duplicates the topmost item on the stack. Stack => (4, 4)

IL_0004:  ldc.i4.1    

Push 1 onto the stack. Stack => (1, 4, 4)

IL_0005:  sub         

Subtract the two top values and push result onto the stack. Stack => (3, 4)

IL_0006:  stloc.0     

Store the topmost value of the stack back to x. Stack => (4)

IL_0007:  ldloc.0     

Load the value of x back into the stack. Stack => (3, 4)

IL_0008:  ldc.i4.1    

Load the value 1 onto the stack. Stack => (1, 3, 4)

IL_0009:  sub         

Subtract the two. Stack => (2, 4)

IL_000A:  dup         

Duplicate the top value => (2, 2, 4)

IL_000B:  stloc.0     

Store the top value back to x. Stack => (2, 4)

IL_000C:  sub      

Subtract the two top values. Stack => (2)

IL_000D:  stloc.0  

Store this value back into x. x == 2