strict data type check

[Sam Sungshik Kong]

Hello!

I studied C# a little bit and am trying to compare it with VB.Net.

There's 'Option Strict' in VB.Net.
I thought that if I turn it on, it is as strict as C# when checking types.

See the following codes.

<vb.net>
Option Strict On
Imports System
Module Main
Sub Main()
Dim S As Short = 0
S += 1 '*******Error!!! It should be S += 1S.
Console.WriteLine(S.ToString())
End Sub
End Module
</vb.net>

The above code generates an error because in the line of S+=1, 1 is integer
and S is Short.

In C#, the same code was compiled ok.

<csharp>
short s = 0;
s += 1; //okay
</csharp>

What is the rule for that?
An integer can be assigned to a short?

If so, VB.Net with 'Option Strict On' is more strict than C#.
What can I do to make C# compiler check very strictly?

Thanks in advance!

Sam

[Ming Chen]

Well, C# compiler is checking very strictly in this case.
The reason it doesn't report any error is that C# defines some Implicit
constant expression conversion rules.

See C# language spec 6.1.6: A constant-expression (Section 7.15) of type int
can be converted to type sbyte, byte, short, ushort, uint, or ulong,
provided the value of the constant-expression is within the range of the
destination type.
So the interger 1 in your code is safely converted into 1S. But if the
number in your code is 65536, which is out of the range of a "short", the
compiler will complain.

Is there any way to make the C# compiler act just like the VB.net one? I
don't know. :(
Provided the C# compiler's behavior is pretty safe, I see no point of doing
so.

Hope it helps.
Ming Chen

"Sam Sungshik Kong" <ss*@chol.net> wrote in message
news:%2****************@TK2MSFTNGP11.phx.gbl...

Hello!

I studied C# a little bit and am trying to compare it with VB.Net.

There's 'Option Strict' in VB.Net.
I thought that if I turn it on, it is as strict as C# when checking types.

See the following codes.

<vb.net>
Option Strict On
Imports System
Module Main
Sub Main()
Dim S As Short = 0
S += 1 '*******Error!!! It should be S += 1S.
Console.WriteLine(S.ToString())
End Sub
End Module
</vb.net>

The above code generates an error because in the line of S+=1, 1 is integer and S is Short.

In C#, the same code was compiled ok.

<csharp>
short s = 0;
s += 1; //okay
</csharp>

What is the rule for that?
An integer can be assigned to a short?

If so, VB.Net with 'Option Strict On' is more strict than C#.
What can I do to make C# compiler check very strictly?

Thanks in advance!

Sam

[Val Savvateev]

Sam,

What you're seeing is by desing. Section "6.1.6 Implicit constant expression
conversions" of C# specs states:

"An implicit constant expression conversion permits the following
conversions:
a.. A constant-expression (Section 7.15) of type int can be converted to
type sbyte, byte, short, ushort, uint, or ulong, provided the value of the
constant-expression is within the range of the destination type.
................."

The mentioned range checking makes such implicit convertions safe, so
there's really no need for "strict" option analogue. In fact I would say
that C# has that options always on compared to VB....

I'd suggest looking through the entire chapter "6. Conversions" to get
better understanding of conversions...

Regards,
Val.
"Sam Sungshik Kong" <ss*@chol.net> wrote in message
news:%2****************@TK2MSFTNGP11.phx.gbl...

Hello!

I studied C# a little bit and am trying to compare it with VB.Net.

There's 'Option Strict' in VB.Net.
I thought that if I turn it on, it is as strict as C# when checking types.

See the following codes.

<vb.net>
Option Strict On
Imports System
Module Main
Sub Main()
Dim S As Short = 0
S += 1 '*******Error!!! It should be S += 1S.
Console.WriteLine(S.ToString())
End Sub
End Module
</vb.net>

The above code generates an error because in the line of S+=1, 1 is integer and S is Short.

In C#, the same code was compiled ok.

<csharp>
short s = 0;
s += 1; //okay
</csharp>

What is the rule for that?
An integer can be assigned to a short?

If so, VB.Net with 'Option Strict On' is more strict than C#.
What can I do to make C# compiler check very strictly?

Thanks in advance!

Sam