What is the dis advantage in using the var type variable?

In my opinion using var forces me to use good names for the variables and ultimately lead to more readable code. I always use var for temporary variables. On the other hand I strive to keep temporary variables to minimum in accordance with good coding practices.

The obvious disadvantage is that you cannot write bad code when using var or the reader would invariably be confused.

It reduces the readability of the code, when someone else is reading your code especially when some person is new to an existing project.

There has been a lot of dispute over the use of var. My general rules are the following.

• When the type is obvious such as when the right hand of the assignment is a constructor, use var.
• When the type is complex to write, such as a LINQ query (the reason for var in the first place) use var.
• For ambivalent types (your Decimal being an example) where you want to make sure that your variable is correctly typed, spell it out.
• Anonymous types have to use var.
• In all other cases spell out the type.

Basically, the goal is to make it easier to read the code. If you feel that var suffices because the assignment is obvious, use var. Use the full type name as a hint for the reader when you feel it's necessary.