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.WriteLi ne(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******** ********@TK2MSF TNGP11.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.WriteLi ne(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******** ********@TK2MSF TNGP11.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.WriteLi ne(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