I put everything in one file for ease of use; also I have #include
<*.hfiles instead of the <*since my compiler is pre-ANSI C so it
needs the .h
#include <iostream.h>
#include <iomanip.h>
#include <string.h>
class Cmd {
public:
virtual ~Cmd() {}
char* printCmd()
{
return _name;
}
protected:
Cmd() {}
char _name[16];
};
class ACmd : public Cmd {
public:
static Cmd* getInstance()
{
if (!_instance) {
_instance=new ACmd;
}
return _instance;
}
~ACmd() {}
private:
ACmd()
{
strcpy(_name, "ACmd");
}
static Cmd* _instance;
};
class BCmd : public Cmd {
public:
static Cmd* getInstance()
{
if (!_instance) {
_instance=new BCmd;
}
return _instance;
}
~BCmd() {}
private:
BCmd()
{
strcpy(_name, "ACmd");
}
static Cmd* _instance;
};
typedef struct {
Cmd* cmd;
} CmdS;
Cmd* ACmd::_instance =NULL;
Cmd* BCmd::_instance =NULL;
int main()
{
Cmd* cmd=ACmd::getIn stance();
Cmd* cmd1=BCmd::getI nstance();
CmdS* cmds=(CmdS*)mal loc(sizeof(CmdS ));
CmdS* cmds1=(CmdS*)ma lloc(sizeof(Cmd S));
cmds->cmd=cmd;
cmds1->cmd=cmd1;
cout << "cmds->cmd: " << cmds->cmd->printCmd()
<< hex << " 0x" << cmds->cmd
<< " ,cmds1->cmd: " << cmds1->cmd->printCmd()
<< " 0x" << cmds1->cmd << endl;
// Uncomment one or the other assignment below...
// This satisfies the if statement below;
// however, the value AND contents of cmds->cmd are
// overwritten
cmds->cmd=cmds1->cmd;
// This does NOT satisfy the if statement below;
// however, the value cmds->cmd are preserved,
// only its contents change
// *cmds->cmd=*cmds1->cmd;
cout << "cmds->cmd: " << cmds->cmd->printCmd()
<< hex << " 0x" << cmds->cmd
<< " ,cmds1->cmd: " << cmds1->cmd->printCmd()
<< " 0x" << cmds1->cmd << endl;
if (cmds->cmd==BCmd::get Instance()) {
cout << "equal" << endl;
}
return 0;
}
Using the first assignment yields; notice how the both value and
content of cmds->cmd changed
cmds->cmd: ACmd 0x0x996e008 ,cmds1->cmd: ACmd 0x0x996e020
cmds->cmd: ACmd 0x0x996e020 ,cmds1->cmd: ACmd 0x0x996e020
equal
Using the second assignment yields; here notice how the value of
cmds->cmd did NOT change, only the content; however the if statement
failed.
cmds->cmd: ACmd 0x0x8c7b008 ,cmds1->cmd: ACmd 0x0x8c7b020
cmds->cmd: ACmd 0x0x8c7b008 ,cmds1->cmd: ACmd 0x0x8c7b020
How can I get this?
cmds->cmd: ACmd 0x0x8c7b008 ,cmds1->cmd: ACmd 0x0x8c7b020
cmds->cmd: ACmd 0x0x8c7b008 ,cmds1->cmd: ACmd 0x0x8c7b020
equal
12  1502 
Zilla wrote:
I put everything in one file for ease of use; also I have #include
<*.hfiles instead of the <*since my compiler is pre-ANSI C so it
needs the .h
#include <iostream.h>
#include <iomanip.h>
#include <string.h>
class Cmd {
public:
virtual ~Cmd() {}
char* printCmd()
{
return _name;
}
protected:
Cmd() {}
char _name[16];
};
class ACmd : public Cmd {
public:
static Cmd* getInstance()
{
if (!_instance) {
_instance=new ACmd;
}
return _instance;
}
~ACmd() {}
private:
ACmd()
{
strcpy(_name, "ACmd");
}
static Cmd* _instance;
};
class BCmd : public Cmd {
public:
static Cmd* getInstance()
{
if (!_instance) {
_instance=new BCmd;
}
return _instance;
}
~BCmd() {}
private:
BCmd()
{
strcpy(_name, "ACmd");
I suspect your error lies here.
}
static Cmd* _instance;
};
typedef struct {
Cmd* cmd;
} CmdS;
On Oct 19, 5:02 pm, red floyd <no.s...@here.d udewrote:
Zilla wrote:
I put everything in one file for ease of use; also I have #include
<*.hfiles instead of the <*since my compiler is pre-ANSI C so it
needs the .h
#include <iostream.h>
#include <iomanip.h>
#include <string.h>
class Cmd {
public:
virtual ~Cmd() {}
char* printCmd()
{
return _name;
}
protected:
Cmd() {}
char _name[16];
};
class ACmd : public Cmd {
public:
static Cmd* getInstance()
{
if (!_instance) {
_instance=new ACmd;
}
return _instance;
}
~ACmd() {}
private:
ACmd()
{
strcpy(_name, "ACmd");
}
static Cmd* _instance;
};
class BCmd : public Cmd {
public:
static Cmd* getInstance()
{
if (!_instance) {
_instance=new BCmd;
}
return _instance;
}
~BCmd() {}
private:
BCmd()
{
strcpy(_name, "ACmd");
I suspect your error lies here.
}
static Cmd* _instance;
};
typedef struct {
Cmd* cmd;
} CmdS;- Hide quoted text -
- Show quoted text -- Hide quoted text -
- Show quoted text -
How? ACmd and BCmd are singletons, and that's how one codes one. See
Design Patterns book.
Zilla wrote:
On Oct 19, 5:02 pm, red floyd <no.s...@here.d udewrote:
>Zilla wrote:
>>I put everything in one file for ease of use; also I have #include
<*.hfiles instead of the <*since my compiler is pre-ANSI C so it
needs the .h
>>#include <iostream.h>
#include <iomanip.h>
#include <string.h>
>>class Cmd {
public:
virtual ~Cmd() {}
char* printCmd()
{
return _name;
}
protected:
Cmd() {}
char _name[16];
};
>>class ACmd : public Cmd {
public:
static Cmd* getInstance()
{
if (!_instance) {
_instance=new ACmd;
}
return _instance;
}
~ACmd() {}
private:
ACmd()
{
strcpy(_name, "ACmd");
}
static Cmd* _instance;
};
>>class BCmd : public Cmd {
public:
static Cmd* getInstance()
{
if (!_instance) {
_instance=new BCmd;
}
return _instance;
}
~BCmd() {}
private:
BCmd()
{
strcpy(_name, "ACmd");
I suspect your error lies here.
>> }
static Cmd* _instance;
};
>>typedef struct {
Cmd* cmd;
} CmdS;- Hide quoted text -
- Show quoted text -- Hide quoted text -
- Show quoted text -
How? ACmd and BCmd are singletons, and that's how one codes one. See
Design Patterns book.
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask
Zilla wrote:
On Oct 19, 5:02 pm, red floyd <no.s...@here.d udewrote:
>Zilla wrote:
>>I put everything in one file for ease of use; also I have #include
<*.hfiles instead of the <*since my compiler is pre-ANSI C so it
needs the .h
>>#include <iostream.h>
#include <iomanip.h>
#include <string.h>
>>class Cmd {
public:
virtual ~Cmd() {}
char* printCmd()
{
return _name;
}
protected:
Cmd() {}
char _name[16];
};
>>class ACmd : public Cmd {
public:
static Cmd* getInstance()
{
if (!_instance) {
_instance=new ACmd;
}
return _instance;
}
~ACmd() {}
private:
ACmd()
{
strcpy(_name, "ACmd");
}
static Cmd* _instance;
};
>>class BCmd : public Cmd {
public:
static Cmd* getInstance()
{
if (!_instance) {
_instance=new BCmd;
}
return _instance;
}
~BCmd() {}
private:
BCmd()
{
strcpy(_name, "ACmd");
I suspect your error lies here.
>> }
static Cmd* _instance;
};
>>typedef struct {
Cmd* cmd;
} CmdS;- Hide quoted text -
- Show quoted text -- Hide quoted text -
- Show quoted text -
How? ACmd and BCmd are singletons, and that's how one codes one. See
Design Patterns book.
You're thinking so much outside the box that you aren't seeing the
obvious mistake. Hint: it's a copy-and-paste error. Look at it again
and this time really try to see what the function is and what it needs
to do (what every statement needs to do), and what it actually does
(and what the effect of it is).
V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask
On Oct 19, 6:01 pm, "Victor Bazarov" <v.Abaza...@com Acast.netwrote:
Zilla wrote:
On Oct 19, 5:02 pm, red floyd <no.s...@here.d udewrote:
Zilla wrote:
I put everything in one file for ease of use; also I have #include
<*.hfiles instead of the <*since my compiler is pre-ANSI C so it
needs the .h
>#include <iostream.h>
#include <iomanip.h>
#include <string.h>
>class Cmd {
public:
virtual ~Cmd() {}
char* printCmd()
{
return _name;
}
protected:
Cmd() {}
char _name[16];
};
>class ACmd : public Cmd {
public:
static Cmd* getInstance()
{
if (!_instance) {
_instance=new ACmd;
}
return _instance;
}
~ACmd() {}
private:
ACmd()
{
strcpy(_name, "ACmd");
}
static Cmd* _instance;
};
>class BCmd : public Cmd {
public:
static Cmd* getInstance()
{
if (!_instance) {
_instance=new BCmd;
}
return _instance;
}
~BCmd() {}
private:
BCmd()
{
strcpy(_name, "ACmd");
I suspect your error lies here.
> }
static Cmd* _instance;
};
>typedef struct {
Cmd* cmd;
} CmdS;- Hide quoted text -
- Show quoted text -- Hide quoted text -
- Show quoted text -
How? ACmd and BCmd are singletons, and that's how one codes one. See
Design Patterns book.
You're thinking so much outside the box that you aren't seeing the
obvious mistake. Hint: it's a copy-and-paste error. Look at it again
and this time really try to see what the function is and what it needs
to do (what every statement needs to do), and what it actually does
(and what the effect of it is).
V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask- Hide quoted text -
- Show quoted text -
Ah, the _name value, but that's beside the point - I don't care what
the names are - make them same. Look at the pointer values that I
print out. TY
On Oct 19, 6:10 pm, Zilla <zill...@bellso uth.netwrote:
On Oct 19, 6:01 pm, "Victor Bazarov" <v.Abaza...@com Acast.netwrote:
Zilla wrote:
On Oct 19, 5:02 pm, red floyd <no.s...@here.d udewrote:
>Zilla wrote:
>>I put everything in one file for ease of use; also I have #include
>><*.hfiles instead of the <*since my compiler is pre-ANSI C so it
>>needs the .h
>>#include <iostream.h>
>>#include <iomanip.h>
>>#include <string.h>
>>class Cmd {
>>public:
>> virtual ~Cmd() {}
>> char* printCmd()
>> {
>> return _name;
>> }
>>protected:
>> Cmd() {}
>> char _name[16];
>>};
>>class ACmd : public Cmd {
>>public:
>> static Cmd* getInstance()
>> {
>> if (!_instance) {
>> _instance=new ACmd;
>> }
>> return _instance;
>> }
>> ~ACmd() {}
>>private:
>> ACmd()
>> {
>> strcpy(_name, "ACmd");
>> }
>> static Cmd* _instance;
>>};
>>class BCmd : public Cmd {
>>public:
>> static Cmd* getInstance()
>> {
>> if (!_instance) {
>> _instance=new BCmd;
>> }
>> return _instance;
>> }
>> ~BCmd() {}
>>private:
>> BCmd()
>> {
>> strcpy(_name, "ACmd");
>I suspect your error lies here.
>> }
>> static Cmd* _instance;
>>};
>>typedef struct {
>> Cmd* cmd;
>>} CmdS;- Hide quoted text -
>- Show quoted text -- Hide quoted text -
>- Show quoted text -
How? ACmd and BCmd are singletons, and that's how one codes one. See
Design Patterns book.
You're thinking so much outside the box that you aren't seeing the
obvious mistake. Hint: it's a copy-and-paste error. Look at it again
and this time really try to see what the function is and what it needs
to do (what every statement needs to do), and what it actually does
(and what the effect of it is).
V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask- Hide quoted text -
- Show quoted text -
Ah, the _name value, but that's beside the point - I don't care what
the names are - make them same. Look at the pointer values that I
print out. TY- Hide quoted text -
- Show quoted text -
Ok here's output for correcte _name cut & paste error
With cmds->cmd=cmds1->cmd; uncommented...
cmds->cmd: ACmd 0x0x40004820 ,cmds1->cmd: BCmd 0x0x40004840
cmds->cmd: BCmd 0x0x40004840 ,cmds1->cmd: BCmd 0x0x40004840
equal
With *cmds->cmd=*cmds1->cmd; uncommented
cmds->cmd: ACmd 0x0x40004820 ,cmds1->cmd: BCmd 0x0x40004840
cmds->cmd: BCmd 0x0x40004820 ,cmds1->cmd: BCmd 0x0x40004840
Again, in the first case, value AND content of cmds->cmd changed, but
if passed. In the seconde case, ONLY content changed, bugt if fails.
I want ONLY content change, and passing if. TY again.
Zilla wrote:
On Oct 19, 6:10 pm, Zilla <zill...@bellso uth.netwrote:
>On Oct 19, 6:01 pm, "Victor Bazarov" <v.Abaza...@com Acast.netwrote:
Again, in the first case, value AND content of cmds->cmd changed, but
if passed. In the seconde case, ONLY content changed, bugt if fails.
I want ONLY content change, and passing if. TY again.
OK, I misunderstood. I figured you were looking at the output and
seeing ACmd multiple times and getting confuse.
Zilla wrote:
On Oct 19, 6:10 pm, Zilla <zill...@bellso uth.netwrote:
>On Oct 19, 6:01 pm, "Victor Bazarov" <v.Abaza...@com Acast.netwrote:
>>Zilla wrote:
On Oct 19, 5:02 pm, red floyd <no.s...@here.d udewrote:
Zilla wrote:
>I put everything in one file for ease of use; also I have #include
><*.hfile s instead of the <*since my compiler is pre-ANSI C so it
>needs the .h
[redacted]
>
Again, in the first case, value AND content of cmds->cmd changed, but
if passed. In the seconde case, ONLY content changed, bugt if fails.
I want ONLY content change, and passing if. TY again.
It could be a compiler bug, especially since your compiler is apparently
ancient (by your own admission).
On Oct 19, 6:59 pm, red floyd <no.s...@here.d udewrote:
Zilla wrote:
On Oct 19, 6:10 pm, Zilla <zill...@bellso uth.netwrote:
On Oct 19, 6:01 pm, "Victor Bazarov" <v.Abaza...@com Acast.netwrote:
>Zilla wrote:
On Oct 19, 5:02 pm, red floyd <no.s...@here.d udewrote:
Zilla wrote:
I put everything in one file for ease of use; also I have #include
<*.hfiles instead of the <*since my compiler is pre-ANSI C so it
needs the .h
[redacted]
Again, in the first case, value AND content of cmds->cmd changed, but
if passed. In the seconde case, ONLY content changed, bugt if fails.
I want ONLY content change, and passing if. TY again.
It could be a compiler bug, especially since your compiler is apparently
ancient (by your own admission).
Thanks, but it's less fundamental than that since it happens in Visual
C++ 2005. I use HPUX 10.20 (for technical reasons) at work. This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics | |
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