Is there a reason why I should not test a set of variables for 0 by testing their product?

Question

Is there a reason why I should not test a set of variables for 0 by testing their product?

Often in my coding in different languages ​​I will test a set of variables to do something if they consist of zeros.

For example (C #):

if( myString.Length * myInt * (myUrl.LastIndexOf(@"\")+1) == 0 )

Instead:

if( myString.Length == 0 || myInt == 0 || myUrl.LastIndexOf(@"\") < 0)

Is there a reason why I should not test this way?

Answer 1

Here are a few reasons. All of them are important, and they do not have a special order.

• . , . : , , if (myObj != null && myObj.Enabled)
• . myString.Length * myInt * myUrl.LastIndexOf(@"\") == 0 if( myString.Length > 0 && myInt != 0 && myUrl.LastIndexOf(@"\") <= 0)? . . , , ? ...
• . &&, , , , . , " , ", , , , , .

Answer 2

, , . , .

, , , "" , , .

Answer 3

, .

, , 65536, - "\". 65536 * myInt * 65536 , 2 ³² int - 32 . , , .

myInt , 65k . (URL- 65k , )

, , , , , 2 . , ( ), ( ), .