Thread: [Dev-C++] Syntax problem??? Parser error??
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From: Devan L. <dli...@co...> - 2003-10-28 18:46:53
Attachments:
dlippman-6.cpp
listp.cpp
|
From the following line of code:
bool empty = aList.isEmpty();
I'm getting this error:
passing `const List' as `this' argument of `bool
List::isEmpty()' discards qualifiers
isEmpty() is a member function that returns a bool
Thank you,
Devan Lippman <dli...@co...>
(617) 571-3017
Using Dev-C++ version: 4.9.8.4
Compiler Log:
Compiler: Default compiler
Building Makefile: "C:\Dev-Cpp\HW6\Makefile.win"
Executing make...
make.exe -f "C:\Dev-Cpp\HW6\Makefile.win" all
g++.exe -c dlippman-6.cpp -o dlippman-6.o -I"C:/Dev-Cpp/include/c++" -I"C:/Dev-
Cpp/include/c++/mingw32" -I"C:/Dev-Cpp/include/c++/backward" -I"C:/Dev-
Cpp/include"
dlippman-6.cpp: In function `void firstElement(const List&, ListItemType&,
bool&)':
dlippman-6.cpp:54: passing `const List' as `this' argument of `bool
List::isEmpty()' discards qualifiers
dlippman-6.cpp:56: passing `const List' as `this' argument of `void
List::retrieve(int, ListItemType&, bool&)' discards qualifiers
dlippman-6.cpp: In function `void lastElement(const List&, ListItemType&,
bool&)':
dlippman-6.cpp:63: passing `const List' as `this' argument of `bool
List::isEmpty()' discards qualifiers
dlippman-6.cpp:63: passing `const List' as `this' argument of `int
List::getLength()' discards qualifiers
dlippman-6.cpp:63: passing `const List' as `this' argument of `void
List::retrieve(int, ListItemType&, bool&)' discards qualifiers
dlippman-6.cpp: In function `void lookupValue(const List&, int, int&, bool&)':
dlippman-6.cpp:75: passing `const List' as `this' argument of `int
List::getLength()' discards qualifiers
dlippman-6.cpp:76: passing `const List' as `this' argument of `void
List::retrieve(int, ListItemType&, bool&)' discards qualifiers
dlippman-6.cpp: In function `void testList()':
dlippman-6.cpp:142: parse error before `{' token
dlippman-6.cpp:149: return-statement with a value, in function declared with a
void return type
dlippman-6.cpp:153: parse error at end of input
make.exe: *** [dlippman-6.o] Error 1
Execution terminated
|
|
From: Per W. <pw...@ia...> - 2003-10-28 18:55:09
|
you have a class
class List {
public:
bool isEmpty();
};
If you rewrite it to:
class List {
public:
bool isEmpty() const;
};
you tell the compiler that isEmpty() will not perform any changes of the
List object. This informs the compiler to allow isEmpty() calls for a
const list object such as:
void my_function(const List& list) {
if (!list.isEmpty()) {
....
}
}
/Per W
On Tue, 28 Oct 2003, Devan Lippman wrote:
> >From the following line of code:
> bool empty = aList.isEmpty();
> I'm getting this error:
> passing `const List' as `this' argument of `bool
> List::isEmpty()' discards qualifiers
>
> isEmpty() is a member function that returns a bool
>
> Thank you,
> Devan Lippman <dli...@co...>
> (617) 571-3017
>
> Using Dev-C++ version: 4.9.8.4
>
> Compiler Log:
> Compiler: Default compiler
> Building Makefile: "C:\Dev-Cpp\HW6\Makefile.win"
> Executing make...
> make.exe -f "C:\Dev-Cpp\HW6\Makefile.win" all
> g++.exe -c dlippman-6.cpp -o dlippman-6.o -I"C:/Dev-Cpp/include/c++" -I"C:/Dev-
> Cpp/include/c++/mingw32" -I"C:/Dev-Cpp/include/c++/backward" -I"C:/Dev-
> Cpp/include"
>
> dlippman-6.cpp: In function `void firstElement(const List&, ListItemType&,
> bool&)':
> dlippman-6.cpp:54: passing `const List' as `this' argument of `bool
>
> List::isEmpty()' discards qualifiers
>
> dlippman-6.cpp:56: passing `const List' as `this' argument of `void
> List::retrieve(int, ListItemType&, bool&)' discards qualifiers
>
> dlippman-6.cpp: In function `void lastElement(const List&, ListItemType&,
> bool&)':
> dlippman-6.cpp:63: passing `const List' as `this' argument of `bool
> List::isEmpty()' discards qualifiers
>
> dlippman-6.cpp:63: passing `const List' as `this' argument of `int
> List::getLength()' discards qualifiers
>
> dlippman-6.cpp:63: passing `const List' as `this' argument of `void
> List::retrieve(int, ListItemType&, bool&)' discards qualifiers
>
> dlippman-6.cpp: In function `void lookupValue(const List&, int, int&, bool&)':
>
> dlippman-6.cpp:75: passing `const List' as `this' argument of `int
> List::getLength()' discards qualifiers
>
> dlippman-6.cpp:76: passing `const List' as `this' argument of `void
> List::retrieve(int, ListItemType&, bool&)' discards qualifiers
>
> dlippman-6.cpp: In function `void testList()':
>
> dlippman-6.cpp:142: parse error before `{' token
>
> dlippman-6.cpp:149: return-statement with a value, in function declared with a
> void return type
>
> dlippman-6.cpp:153: parse error at end of input
>
> make.exe: *** [dlippman-6.o] Error 1
>
> Execution terminated
>
>
>
|
|
From: Alvin T. <al...@th...> - 2003-10-28 19:17:54
|
i didn't know that either. does the compiler actually check the code to
see if it tries to modify the List (and generate a compile error if it
does), or is it more like a "gentleman's agreement"?
-alvin
Per Westermark wrote:
> you have a class
>
> class List {
> public:
> bool isEmpty();
> };
>
> If you rewrite it to:
>
> class List {
> public:
> bool isEmpty() const;
> };
>
> you tell the compiler that isEmpty() will not perform any changes of the
> List object. This informs the compiler to allow isEmpty() calls for a
> const list object such as:
>
> void my_function(const List& list) {
> if (!list.isEmpty()) {
> ....
> }
> }
>
> /Per W
>
> On Tue, 28 Oct 2003, Devan Lippman wrote:
>
>
>>>From the following line of code:
>> bool empty = aList.isEmpty();
>>I'm getting this error:
>> passing `const List' as `this' argument of `bool
>> List::isEmpty()' discards qualifiers
>>
>>isEmpty() is a member function that returns a bool
>>
>>Thank you,
>>Devan Lippman <dli...@co...>
>>(617) 571-3017
>>
>>Using Dev-C++ version: 4.9.8.4
>>
>>Compiler Log:
>>Compiler: Default compiler
>>Building Makefile: "C:\Dev-Cpp\HW6\Makefile.win"
>>Executing make...
>>make.exe -f "C:\Dev-Cpp\HW6\Makefile.win" all
>>g++.exe -c dlippman-6.cpp -o dlippman-6.o -I"C:/Dev-Cpp/include/c++" -I"C:/Dev-
>>Cpp/include/c++/mingw32" -I"C:/Dev-Cpp/include/c++/backward" -I"C:/Dev-
>>Cpp/include"
>>
>>dlippman-6.cpp: In function `void firstElement(const List&, ListItemType&,
>> bool&)':
>>dlippman-6.cpp:54: passing `const List' as `this' argument of `bool
>>
>> List::isEmpty()' discards qualifiers
>>
>>dlippman-6.cpp:56: passing `const List' as `this' argument of `void
>> List::retrieve(int, ListItemType&, bool&)' discards qualifiers
>>
>>dlippman-6.cpp: In function `void lastElement(const List&, ListItemType&,
>> bool&)':
>>dlippman-6.cpp:63: passing `const List' as `this' argument of `bool
>> List::isEmpty()' discards qualifiers
>>
>>dlippman-6.cpp:63: passing `const List' as `this' argument of `int
>> List::getLength()' discards qualifiers
>>
>>dlippman-6.cpp:63: passing `const List' as `this' argument of `void
>> List::retrieve(int, ListItemType&, bool&)' discards qualifiers
>>
>>dlippman-6.cpp: In function `void lookupValue(const List&, int, int&, bool&)':
>>
>>dlippman-6.cpp:75: passing `const List' as `this' argument of `int
>> List::getLength()' discards qualifiers
>>
>>dlippman-6.cpp:76: passing `const List' as `this' argument of `void
>> List::retrieve(int, ListItemType&, bool&)' discards qualifiers
>>
>>dlippman-6.cpp: In function `void testList()':
>>
>>dlippman-6.cpp:142: parse error before `{' token
>>
>>dlippman-6.cpp:149: return-statement with a value, in function declared with a
>> void return type
>>
>>dlippman-6.cpp:153: parse error at end of input
>>
>>make.exe: *** [dlippman-6.o] Error 1
>>
>>Execution terminated
>>
>>
>>
>
>
>
>
> -------------------------------------------------------
> This SF.net email is sponsored by: SF.net Giveback Program.
> Does SourceForge.net help you be more productive? Does it
> help you create better code? SHARE THE LOVE, and help us help
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|
|
From: P.D. v. Z. <pa...@my...> - 2003-10-28 19:28:35
|
It gets checked. The "this" pointer passed to const member functions is
const as well, so any attempt to modify member variables (or call non-const
member functions) will result in errors.
-----Original Message-----
From: dev...@li...
[mailto:dev...@li...] On Behalf Of Alvin
Thompson
Sent: Tuesday, October 28, 2003 8:20 PM
To: Per Westermark
Cc: de...@li...; dev...@li...
Subject: Re: [Dev-C++] Syntax problem??? Parser error??
i didn't know that either. does the compiler actually check the code to
see if it tries to modify the List (and generate a compile error if it
does), or is it more like a "gentleman's agreement"?
-alvin
Per Westermark wrote:
> you have a class
>
> class List {
> public:
> bool isEmpty();
> };
>
> If you rewrite it to:
>
> class List {
> public:
> bool isEmpty() const;
> };
>
> you tell the compiler that isEmpty() will not perform any changes of the
> List object. This informs the compiler to allow isEmpty() calls for a
> const list object such as:
>
> void my_function(const List& list) {
> if (!list.isEmpty()) {
> ....
> }
> }
>
> /Per W
>
> On Tue, 28 Oct 2003, Devan Lippman wrote:
>
>
>>>From the following line of code:
>> bool empty = aList.isEmpty();
>>I'm getting this error:
>> passing `const List' as `this' argument of `bool
>> List::isEmpty()' discards qualifiers
>>
>>isEmpty() is a member function that returns a bool
>>
>>Thank you,
>>Devan Lippman <dli...@co...>
>>(617) 571-3017
>>
>>Using Dev-C++ version: 4.9.8.4
>>
>>Compiler Log:
>>Compiler: Default compiler
>>Building Makefile: "C:\Dev-Cpp\HW6\Makefile.win"
>>Executing make...
>>make.exe -f "C:\Dev-Cpp\HW6\Makefile.win" all
>>g++.exe -c dlippman-6.cpp -o dlippman-6.o -I"C:/Dev-Cpp/include/c++"
-I"C:/Dev-
>>Cpp/include/c++/mingw32" -I"C:/Dev-Cpp/include/c++/backward" -I"C:/Dev-
>>Cpp/include"
>>
>>dlippman-6.cpp: In function `void firstElement(const List&, ListItemType&,
>> bool&)':
>>dlippman-6.cpp:54: passing `const List' as `this' argument of `bool
>>
>> List::isEmpty()' discards qualifiers
>>
>>dlippman-6.cpp:56: passing `const List' as `this' argument of `void
>> List::retrieve(int, ListItemType&, bool&)' discards qualifiers
>>
>>dlippman-6.cpp: In function `void lastElement(const List&, ListItemType&,
>> bool&)':
>>dlippman-6.cpp:63: passing `const List' as `this' argument of `bool
>> List::isEmpty()' discards qualifiers
>>
>>dlippman-6.cpp:63: passing `const List' as `this' argument of `int
>> List::getLength()' discards qualifiers
>>
>>dlippman-6.cpp:63: passing `const List' as `this' argument of `void
>> List::retrieve(int, ListItemType&, bool&)' discards qualifiers
>>
>>dlippman-6.cpp: In function `void lookupValue(const List&, int, int&,
bool&)':
>>
>>dlippman-6.cpp:75: passing `const List' as `this' argument of `int
>> List::getLength()' discards qualifiers
>>
>>dlippman-6.cpp:76: passing `const List' as `this' argument of `void
>> List::retrieve(int, ListItemType&, bool&)' discards qualifiers
>>
>>dlippman-6.cpp: In function `void testList()':
>>
>>dlippman-6.cpp:142: parse error before `{' token
>>
>>dlippman-6.cpp:149: return-statement with a value, in function declared
with a
>> void return type
>>
>>dlippman-6.cpp:153: parse error at end of input
>>
>>make.exe: *** [dlippman-6.o] Error 1
>>
>>Execution terminated
>>
>>
>>
>
>
>
>
> -------------------------------------------------------
> This SF.net email is sponsored by: SF.net Giveback Program.
> Does SourceForge.net help you be more productive? Does it
> help you create better code? SHARE THE LOVE, and help us help
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-------------------------------------------------------
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|
From: Alvin T. <al...@th...> - 2003-10-28 20:50:00
|
ah, i see!
-alvin
P.D. van Zelst wrote:
> It gets checked. The "this" pointer passed to const member functions is
> const as well, so any attempt to modify member variables (or call non-const
> member functions) will result in errors.
>
>
> -----Original Message-----
> From: dev...@li...
> [mailto:dev...@li...] On Behalf Of Alvin
> Thompson
> Sent: Tuesday, October 28, 2003 8:20 PM
> To: Per Westermark
> Cc: de...@li...; dev...@li...
> Subject: Re: [Dev-C++] Syntax problem??? Parser error??
>
> i didn't know that either. does the compiler actually check the code to
> see if it tries to modify the List (and generate a compile error if it
> does), or is it more like a "gentleman's agreement"?
>
> -alvin
>
>
> Per Westermark wrote:
>
>
>>you have a class
>>
>>class List {
>>public:
>> bool isEmpty();
>>};
>>
>>If you rewrite it to:
>>
>>class List {
>>public:
>> bool isEmpty() const;
>>};
>>
>>you tell the compiler that isEmpty() will not perform any changes of the
>>List object. This informs the compiler to allow isEmpty() calls for a
>>const list object such as:
>>
>>void my_function(const List& list) {
>> if (!list.isEmpty()) {
>> ....
>> }
>>}
>>
>>/Per W
>>
>>On Tue, 28 Oct 2003, Devan Lippman wrote:
>>
>>
>>
>>>>From the following line of code:
>>> bool empty = aList.isEmpty();
>>>I'm getting this error:
>>> passing `const List' as `this' argument of `bool
>>> List::isEmpty()' discards qualifiers
>>>
>>>isEmpty() is a member function that returns a bool
>>>
>>>Thank you,
>>>Devan Lippman <dli...@co...>
>>>(617) 571-3017
>>>
>>>Using Dev-C++ version: 4.9.8.4
>>>
>>>Compiler Log:
>>>Compiler: Default compiler
>>>Building Makefile: "C:\Dev-Cpp\HW6\Makefile.win"
>>>Executing make...
>>>make.exe -f "C:\Dev-Cpp\HW6\Makefile.win" all
>>>g++.exe -c dlippman-6.cpp -o dlippman-6.o -I"C:/Dev-Cpp/include/c++"
>
> -I"C:/Dev-
>
>>>Cpp/include/c++/mingw32" -I"C:/Dev-Cpp/include/c++/backward" -I"C:/Dev-
>>>Cpp/include"
>>>
>>>dlippman-6.cpp: In function `void firstElement(const List&, ListItemType&,
>>> bool&)':
>>>dlippman-6.cpp:54: passing `const List' as `this' argument of `bool
>>>
>>> List::isEmpty()' discards qualifiers
>>>
>>>dlippman-6.cpp:56: passing `const List' as `this' argument of `void
>>> List::retrieve(int, ListItemType&, bool&)' discards qualifiers
>>>
>>>dlippman-6.cpp: In function `void lastElement(const List&, ListItemType&,
>>> bool&)':
>>>dlippman-6.cpp:63: passing `const List' as `this' argument of `bool
>>> List::isEmpty()' discards qualifiers
>>>
>>>dlippman-6.cpp:63: passing `const List' as `this' argument of `int
>>> List::getLength()' discards qualifiers
>>>
>>>dlippman-6.cpp:63: passing `const List' as `this' argument of `void
>>> List::retrieve(int, ListItemType&, bool&)' discards qualifiers
>>>
>>>dlippman-6.cpp: In function `void lookupValue(const List&, int, int&,
>
> bool&)':
>
>>>dlippman-6.cpp:75: passing `const List' as `this' argument of `int
>>> List::getLength()' discards qualifiers
>>>
>>>dlippman-6.cpp:76: passing `const List' as `this' argument of `void
>>> List::retrieve(int, ListItemType&, bool&)' discards qualifiers
>>>
>>>dlippman-6.cpp: In function `void testList()':
>>>
>>>dlippman-6.cpp:142: parse error before `{' token
>>>
>>>dlippman-6.cpp:149: return-statement with a value, in function declared
>
> with a
>
>>> void return type
>>>
>>>dlippman-6.cpp:153: parse error at end of input
>>>
>>>make.exe: *** [dlippman-6.o] Error 1
>>>
>>>Execution terminated
>>>
>>>
>>>
>>
>>
>>
>>
>>-------------------------------------------------------
>>This SF.net email is sponsored by: SF.net Giveback Program.
>>Does SourceForge.net help you be more productive? Does it
>>help you create better code? SHARE THE LOVE, and help us help
>>YOU! Click Here: http://sourceforge.net/donate/
>>_______________________________________________
>>Dev-cpp-users mailing list
>>Dev...@li...
>>TO UNSUBSCRIBE: http://www23.brinkster.com/noicys/devcpp/ub.htm
>>https://lists.sourceforge.net/lists/listinfo/dev-cpp-users
>
>
>
>
> -------------------------------------------------------
> This SF.net email is sponsored by: SF.net Giveback Program.
> Does SourceForge.net help you be more productive? Does it
> help you create better code? SHARE THE LOVE, and help us help
> YOU! Click Here: http://sourceforge.net/donate/
> _______________________________________________
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> TO UNSUBSCRIBE: http://www23.brinkster.com/noicys/devcpp/ub.htm
> https://lists.sourceforge.net/lists/listinfo/dev-cpp-users
>
>
>
>
> -------------------------------------------------------
> This SF.net email is sponsored by: SF.net Giveback Program.
> Does SourceForge.net help you be more productive? Does it
> help you create better code? SHARE THE LOVE, and help us help
> YOU! Click Here: http://sourceforge.net/donate/
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