Reputation: 55739

Operator precedence in C#

(int)(int1 / (float)var2.Count() * 100)

equivalent to

(int)((int1 / (float)var2.Count()) * 100)

...and will it use floating point or integer division?

Edit... if the answer is yes to the above, what is the advantage of performing a floating point division here?

Upvotes: 8

Answers (8)

Jordão

Reputation: 56477

Precedence rules are really annoying to remember, so I too prefer to use brackets to disambiguate. I try to follow the advice to "write code for people first, computers second". But, there's an interesting mnemonic (that I learned from Bruce Eckel's books) to remember (some of) the rules: "Ulcer Addicts Really Like C A lot":

Ulcer   - Unary (+, -, ++, --, !)
Addicts - Arithmetic (and shift) (+, -, *, /, %, <<, >>)
Really  - Relational (<, >, ==, <=, >=, !=)
Like    - Logical (and bitwise) (&&, ||, &, |, ^)
C       - Conditional ( ? : ) <- this is the conditional ternary operator
A lot   - Assignment ( =, *=, +=, ...)

It's not perfect, bitwise operators are squeezed in and we have to know that multiplication operators (*, /, %) take precedence over addition ones (+, -).

Upvotes: 3

dan-gph

Reputation: 16909

See the C# Language Specification: Operator precedence and associativity.

Upvotes: 1

Anton Hansson

Reputation: 2171

They are equivalent and it will use floating point division. Even if the multiplication happened first, floating point division would be used since the int is divided by the result of float*int which is float.

Edit:

If the answer is yes to the above, what is the advantage of performing a floating point division here?

Is it an advantage? The first thing that you should be considering is whether or not it's correct since the result will be different. Judging by the code it seems you are trying to calculate some percentage. When using integer divison, if "int1" is always smaller than var2.Count() the result will always be 0 which might not be what you want.

Upvotes: 2