why does this execute the else clause

[noname]

char c ='\0';
string cstr = "";
string cstr2;
cstr2 =cstr + c;
//Debugger watch on cstr2.Length shows 0
if( cstr2.Length == 0)
{
MessageBox.Show ("in if",
cstr2,MessageBoxButtons.OKCancel,
MessageBoxIcon.Asterisk);
}
else
{
MessageBox.Show ("in else",
cstr2,MessageBoxButtons.OKCancel,
MessageBoxIcon.Asterisk);
}

why does this execute the else clause

[Jon Skeet]

noname <no****@noname.com> wrote:

char c ='\0';
string cstr = "";
string cstr2;
cstr2 =cstr + c;
//Debugger watch on cstr2.Length shows 0
if( cstr2.Length == 0)
{
MessageBox.Show ("in if",
cstr2,MessageBoxButtons.OKCancel,
MessageBoxIcon.Asterisk);
}
else
{
MessageBox.Show ("in else",
cstr2,MessageBoxButtons.OKCancel,
MessageBoxIcon.Asterisk);
}

why does this execute the else clause

Because the string's length isn't 0. It's 1 - it has a single
character, which is the null character. The debugger is showing the
wrong thing here, but the execution is correct.

--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet/
If replying to the group, please do not mail me too

[Val Savvateev]

Because cstr2's length is 1. C# strings _can_ contain zeroes; unlike C/C++
strings they're _not_ zero-terminated. (Closest analogy would be BSTRs)

"noname" <no****@noname.com> wrote in message
news:02****************************@phx.gbl...

char c ='\0';
string cstr = "";
string cstr2;
cstr2 =cstr + c;
//Debugger watch on cstr2.Length shows 0
if( cstr2.Length == 0)
{
MessageBox.Show ("in if",
cstr2,MessageBoxButtons.OKCancel,
MessageBoxIcon.Asterisk);
}
else
{
MessageBox.Show ("in else",
cstr2,MessageBoxButtons.OKCancel,
MessageBoxIcon.Asterisk);
}

why does this execute the else clause

[Paul E Collins]

"noname" <no****@noname.com> wrote:

char c ='\0';
string cstr = "";
string cstr2;
cstr2 =cstr + c;
//Debugger watch on cstr2.Length shows 0

For me, it shows 1. Are you sure you checked the watch *after* that
statement had executed?

The else clause executes because a string containing a null character isn't
an empty string.

P.

--
www.CL4.org

[Jon Skeet]

Paul E Collins <fi******************@CL4.org> wrote:

"noname" <no****@noname.com> wrote:

char c ='\0';
string cstr = "";
string cstr2;
cstr2 =cstr + c;
//Debugger watch on cstr2.Length shows 0

For me, it shows 1. Are you sure you checked the watch *after* that
statement had executed?

It could be because the OP is using an unpatch version of VS.NET 2002 -
I seem to remember that there were various bugs when watching strings
in VS.NET 2002.

--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet/
If replying to the group, please do not mail me too

[Hans Kamp]

"noname" <no****@noname.com> schreef in bericht
news:02****************************@phx.gbl...

char c ='\0';
string cstr = "";
string cstr2;
cstr2 =cstr + c;
//Debugger watch on cstr2.Length shows 0

I have tested this with Borland C#Builder. The watch tells me that
cstr.Length = 1. So there is a bug in the debugger of the compiler that you
use.

Hans Kamp.

[Hans Kamp]

"Tu-Thach" <tu*****@yahoo.com> schreef in bericht
news:02****************************@phx.gbl...

The else is executed because cstr2.Length is greater than
0. Maybe something is strange with your debugger.

I think it is, because the debugger of the compiler that I use (C#Builder)
doesn't show this bug, and shows "1" for cstr2.Length.

Hans Kamp.

[Hans Kamp]

"Paul E Collins" <fi******************@CL4.org> schreef in bericht
news:bi**********@hercules.btinternet.com...

"noname" <no****@noname.com> wrote:

char c ='\0';
string cstr = "";
string cstr2;
cstr2 =cstr + c;
//Debugger watch on cstr2.Length shows 0

For me, it shows 1. Are you sure you checked the watch *after* that
statement had executed?

At the start the debugger shows:

cstr2 "null"
cstr2.Length function call terminated by exception

After:

char c ='\0';
string cstr = "";
string cstr2;

it shows:

cstr2 "null"
cstr2.Length function call terminated by exception

After:

cstr2 = cstr + c;

it shows:

cstr ""
cstr2.Length 1

Hans Kamp.