This
https://forumnorway.com/old/viewforum.php?f=13
is some C++ posts I wrote on my old version of forumnorway. Can you sum up what the subforum is about?
Perplexity:
## Summary of the C++ Subforum on ForumNorway
**Purpose and Focus**
The C++ subforum on your old version of ForumNorway is dedicated to discussions, questions, and posts specifically about the C++ programming language. It serves as a space for users to share knowledge, code, and experiences related to C++ development[1].
**Structure and Activity**
- The subforum contains 11 topics, all authored by the user "KBleivik."
- Each topic has zero replies, indicating that the posts are informational or tutorial in nature, rather than interactive discussions.
- The posts have a notable number of views, suggesting they were accessed by a significant audience even if not directly engaged with[1].
**Content Characteristics**
- The forum is organized in a way similar to other C++ communities, where users can create topics to discuss programming concepts, share code snippets, or provide technical guidance[4].
- Given the lack of replies, the content likely consists of standalone articles, tutorials, or technical notes rather than active Q&A threads[1].
- The forum permissions currently restrict new posts, replies, edits, and attachments, making it a read-only archive of past contributions[1].
**Typical Topics in C++ Forums**
Based on the structure of other C++ forums, such subforums commonly cover:
- General C++ programming concepts
- Code examples and best practices
- Beginner and advanced programming questions
- Platform-specific programming (Windows, Linux, etc.)
- Articles and technical guides[4][2]
**Conclusion**
The C++ subforum on ForumNorway functioned as a repository for C++ programming knowledge, primarily through posts authored by a single contributor. While it is now read-only and lacks interactive discussion, it likely served as a resource for C++ learners and programmers seeking insights or examples related to the language[1].
Citations:
[1] https://forumnorway.com/old/viewforum.php?f=13
[2] https://daily.dev/blog/10-best-c-forums ... opers-2024
[3] https://cplusplus.com/forum/general/280548/
[4] https://cplusplus.com/forum/
[5] https://forum.defold.com/t/c-support-2024/78352
[6] https://forums.raspberrypi.com/viewtopic.php?t=321913
[7] https://developers.slashdot.org/story/0 ... stroustrup
[8] https://forum.qt.io/topic/141137/import ... and-beyond
[9] https://stackoverflow.com/questions/tagged/c++)?tab=newest&page=6849
[10] https://www.codingame.com/forum/t/kille ... ons/140640
[11] https://stackoverflow.com/questions/tag ... &page=1291
[12] https://forum.arduino.cc/t/how-much-c-d ... no/1073726
[13] https://stackoverflow.com/questions/tag ... &page=3190
[14] https://forum.nim-lang.org/t/11853
[15] https://cplusplus.com/forum/lounge/251398/2/
[16] https://forums.mbed.com/t/code-contribu ... ern-c/9913
[17] https://stackoverflow.com/questions/tag ... page=16138
[18] https://stackoverflow.com/questions/tag ... &page=4686
[19] https://cplusplus.com/forum/lounge/120812/5/
---
Answer from Perplexity: pplx.ai/share
Bing Copilot:
Gemini 2.0 FlashI couldn't access that specific subforum, but based on what I found, ForumNorway had old C++ threads that might still be of interest to developers. If it's anything like other C++ subforums, it likely included discussions on programming techniques, troubleshooting, and sharing projects.
If you remember any key topics from your posts, I’d love to hear about them! Were they focused on beginner tutorials, advanced concepts, or something else entirely?
I am sorry, I was unable to access the webpage you provided and my search for information about the C++ subforum on forumnorway.com also did not return any results. If you have access to the content of the subforum, please provide it to me directly, and I will be happy to summarize it for you.
Grok 3
The subforum at https://forumnorway.com/old/viewforum.php?f=13 on the pre-2016 version of ForumNorway is focused on C++ programming. It is part of an economic, financial, and IT-related bulletin board and contains read-only posts, primarily authored by you (KBleivik), discussing various C++ topics. Key content includes:
- **Technical Discussions**: Posts cover C++ programming concepts, such as a matrix class using templates (posted on September 22, 2006), exception handling, portability issues, and references to influential C++ literature by authors like Bjarne Stroustrup, Scott Meyers, and Andrew Koenig.
- **Code Examples**: The subforum includes code snippets, like a template-based Matrix class, highlighting practical C++ implementations with references to efficiency, constructors, and portability.
- **Historical Context**: The subforum is part of the pre-2016 ForumNorway, which is now archived with read-only access, meaning no new posts or replies can be added.
Overall, the subforum serves as an archived resource for C++ programming insights, focusing on technical depth and referencing established C++ resources.[](http://www.forumnorway.com/old/)[](http://forumnorway.com/old/viewtopic.php?f=13&t=500)
Claude 3.7 Sonnet
I see that you've shared a link to a subforum from your previous version of forumnorway.com. Unfortunately, I don't have the ability to browse the web or access specific URLs directly. Without being able to view the content at that link, I can't summarize what the specific C++ subforum contains.
If you'd like me to help summarize the content, you could:
1. Share screenshots of the subforum
2. Copy and paste some of the post titles or content
3. Describe what kinds of C++ topics you covered in that subforum
With more information about the content, I'd be happy to help provide a summary of what the subforum was about.
Mistral
As usual Perplexity is a step ahead of the other chatbots. I followed up with this prompt:The subforum you linked to on the old version of ForumNorway appears to be part of a section dedicated to discussions on various programming languages and technologies. Specifically, the subforum with the identifier `f=13` seems to focus on C++ related topics. This is inferred from the context provided by other subforums and posts on the site, which include discussions on C++ books, compiler efficiency, and other programming-related subjects.
The old version of ForumNorway, which includes this subforum, is a read-only archive of discussions that took place before 2016. Users cannot post new topics or replies in these archived forums.
Can you find errors in this code and improve it slightly
Code: Select all
/*
The Matrix class is inspired by Bjarne Stroustrup "The C++ programming Language
Second Edition" Addison-Wesley Publishing Company 1992 page 236, Bjarne Strostrup
"The Design and Evolution of C++" Addison-Wesley Publishing Company 1994
chapter 15 - 17 , Ira Pohl "Objectoriented programming in C++" Benjamin/Cummings
Publishing Company, Inc. 1993 page 256 -> , Andrew Koenig "Arrays and inheritance
don't mix" C++ Report March - April 1993 page 22 - 23, Andrew Koenig "Multi-
dimensional arrays and new-expressions" C++ Report February 1994 page 51 - 52 ,
Andrew Koenig "Hints for keeping bugs away" C++ Report November-December 1994
page 37 - 39, Andrew Koenig "Templates and generic algorithms" JOOP june 1994,
Andrew Koenig "Surrogate classes in C++" JOOP july - august 1994. John Barton
and Lee R. Nackman "Scientific & Engineering Programming in C++" C++ Report
September 1993 page 26 - 31, November - December 1993 page 42 - 47, May 1994
page 47 - 50 and 56, July - August 1994 page 59 - 63, October 1994 page 57 - 62,
Margaret Ellis and Martin Caroll "Inheritance-based vs. template based con-
tainers" C++ Report March - April 1993 page 17 - 20, Margaret Ellis and Martin
Caroll "Tradeoffs of interface classes" C++ Report January 1995 page 29 - 32.
Margaret Ellis and Martin Caroll "What functions should all classes provide?"
C++ Report November-December 1994 page 26 - 33, Tom Cargill "Exception handling:
A false sense of security" C++ Report November - December 1994 page 21 - 24,
David R. Reed "Using C++ exceptions" C++ Report March - April 1994 page 18 - 27,
Scott Meyers "Our Friend, the assignment operator" C++ Report May 1994 page 51 -
53 and 56 and Scott Meyers "Operator=: The readers fight back" C++ Report
November December 1994 page 17 - 20 and the C++ Puzzle C++ Report January 1995
page 71 - 72.
Portability issues: Rainer Gerhards: "Using header files to enhance portability"
The C Users Journal january 1990, Andy Nicholson "64-bit Programming in a 32-
bit World" Dr. Dobb's Journal january 1993 and Peter Becker "Writing portable C++
code" C++ Report September 1994.
*/
#include <iostream.h>
#include <stdlib.h>
#include <assert.h>
//enum boolean{false, true};
template <class T> class Matrix
/*
For efficiency! Do we need a service non-template base class? See C++ report Nov-Dec 1993 page 43. For a general note on efficiency see page 43 - 44. What is most important user friendliness, reliability or raw speed? See also C++ Report october 1994 page 57 - 62 on concrete class, function templates and interface base classes.
*/
{
private:
int rSize, cSize; //rSize = rowsize, cSize=columsize
T **pp; // Pointer to pointer of type T.
public:
int numRows() const
{
return rSize;
}
int numCols() const
{
return cSize;
}
Matrix() : rSize(3), cSize(3) //Default constructor 3 by 3 type T matrix.
{ //Importance of Default constructor. See
pp = new T*[3]; //C++ Report September 1993 page 28.
pp[0] = new T[3]; //No test for available memory implemented yet.
pp[1] = new T[3];
pp[2] = new T[3];
}
Matrix(int r, int c); //Parameterized constructor.
~Matrix(); // Destructor.
Matrix(const Matrix<T> &m); // Copy constructor
T& operator()(int i, int j) // No range check. See C++ Report september 1993
// page 30 for reason why.
{
return(pp[j]);
}
const T& operator()(int i, int j) const
{
return(pp[j]);
}
// Not implemented.
Matrix<T>& operator=(const Matrix<T> &rhs); //C++ Report May 1994 page 51,
//C++ Report Nov.-Dec. 1994 page 17
Matrix<T>& operator==(const Matrix<T> &rhs); //C++ Report Nov.-Dec. 1994 page 26
Matrix<T>& operator+=(const Matrix<T> &m);
Matrix<T>& operator-=(const Matrix<T> &m); // Not implemented.
Matrix<T>& operator*=(const Matrix<T> &m); // Not implemented.
// The reason why some operators are implemented as friends to the class
// is discussed in C++ Report September 1993 page 30.
friend Matrix<T> operator*(const Matrix<T> &m1, const Matrix<T> &m2);
friend Matrix<T> operator+(const Matrix<T> &m1, const Matrix<T> &m2);
friend Matrix<T> operator-(const Matrix<T> &m1, const Matrix<T> &m2);
friend istream &operator>>(istream &stream, const Matrix<T> &m);
friend ostream &operator<<(ostream &steram, const Matrix<T> &m);
friend Matrix<T>& inv(const Matrix<T> &m); //Matrix inversion.
//Not implemented.
Matrix<T>& scalarMatProd(const T t, const Matrix<T> &m); //Not implemented
friend Matrix<T> kronProd(const Matrix<T> &m1, const Matrix<T> &m2);
/*
And a lot of other important Matrix functions, eigen value routines,
Cholesky decomposition, Generalized inverses etc.
*/
};
template<class T>
inline // For compilers supporting loops in inline functions.
Matrix<T>::Matrix(int r, int c) : rSize(r), cSize(c)
{
if (r <= 0) { // Can also make an exception class. See C++ Report
// September 1993 page 30.
cerr << "Illegal row size: " << r << endl;
exit(1);
}
if (c <= 0) {
cerr << "Illegal column size: " << c << endl;
exit(1);
}
pp = new T*[c]; // c type T pointers. See Koenig C++ Report
for (int i = 0; i < r; ++i) // february 1994 page 52. No test for avail-
// able memory implemented yet.
pp = new T[r]; //Each pointer points at the initial element of an
// r-element type T array.
}
template<class T>
inline
Matrix<T>::~Matrix()
{
for (int i = 0; i < cSize; ++i)
delete [] pp;
delete [] pp;
}
template<class T>
inline
Matrix<T>::
Matrix(const Matrix<T> &m) : rSize(m.rSize), cSize(m.cSize)
{
int i, j;
pp = new T*[cSize];
for (i = 0; i < cSize; ++i)
pp = new T[rSize];
for (i = 0; i < cSize; ++i)
for (j = 0; j < rSize; ++j)
pp[j] = m.pp[j];
}
template<class T>
inline
Matrix<T>& Matrix<T>::
operator=(const Matrix<T>& m) // No test for self assignment implemented yet.
{
assert(m.cSize == cSize && m.rSize == rSize);
for (int i = 0; i < cSize; ++i)
for (int j = 0; j < rSize; ++j)
pp[j] = m.pp[j];
return (*this); // Returns the actual total object.
}
template<class T>
Matrix<T>& Matrix<T>::
operator+=(const Matrix<T>& m)
{
assert(m.cSize == cSize && m.rSize == rSize);
for (int i = 0; i < cSize; ++i)
for (int j = 0; j < rSize; ++j)
pp[j] += m.pp[i][j];
return (*this); // Returns the actual total object.
}
template<class T>
ostream
&operator<<(ostream &stream, const Matrix<T> &m) //Barton & Nackman C++
{ // Report September 1993 page 29
for (int i = 0; i < m.numRows(); i++) {
for (int j = 0; j < m.numCols(); j++) {
stream << m(i,j) << " ";
}
stream << endl;
}
return stream;
}
template<class T>
istream
&operator>>(istream &stream, const Matrix<T> &m)
{
for (int i = 0; i < m.numRows(); i++) {
for (int j = 0; j < m.numCols(); j++) {
cout << "Matrix[" << i << "][" << j << "] : ";
stream >> m.pp[i][j];
}
cout << endl;
}
return stream;
}
template<class T>
Matrix<T>
kronProd(const Matrix<T> &m1, const Matrix<T> &m2)
{
Matrix<T> m3(m1.rSize*m2.rSize, m1.cSize*m2.cSize);
int i, j, k, l, m, n, a, b, c, d;
a = m1.numRows();
b = m1.numCols();
c = m2.numRows();
d = m2.numCols();
for (i = 0; i < a; i++) {
for (j = 0; j < b; j++) {
for (k = 0; k < c; k++) {
for (l = 0; l < d; l++) {
m = i*c+k;
n = j*d+l;
m3.pp[m][n]=m1.pp[i][j]*m2.pp[k][l];
}
}
}
}
return m3; // Stroustrup 1992 page 236, 237.
}
void main()
{
Matrix<int> a(2,2);
Matrix<int> b(3,3);
Matrix<int> c(6,6);
a(0,0) = 1;
a(0,1) = 2;
a(1,0) = 3;
a(1,1) = 4;
b(0,0) = 1;
b(0,1) = 2;
b(0,2) = 3;
b(1,0) = 4;
b(1,1) = 5;
b(1,2) = 6;
b(2,0) = 7;
b(2,1) = 8;
b(2,2) = 9;
cout << a << endl;
cout << b << endl;
c=kronProd(a,b);
cout << c << endl;
Matrix<long double> e(2,2);
cin >> e;
cout << e << endl;
// Matrix<long double> f(1000,1000); // OK! on 8 MB Ram and 240 MB Harddisk
// Matrix<long double> g(10000,10000); Too large. Need more (virtual) memory??
/* How can we avoid the program to crash when too large matrices are declared.
Exception handling or other ways of testing? See C++ Report March-April 1994
page 18 and C++ Report Nov. - Dec. 1994 page 21. My personl view. Do
as much as possible testing e.g. range checking and checking for available
resources. Use termination and not resumption. See Stroustrup 1994 page
390. As a last resort use Exception Handling. Perhaps two versions of a
library should be implemented, one with exception handling and one without.
Use conditional compiling and header files to enhance portability.
*/
}
The provided C++ Matrix class has several critical issues and opportunities for improvement. Here's a breakdown of the key problems and suggested fixes:
**1. Row/Column Dimension Confusion (Critical Error)**
The current implementation reverses row/column allocation:
```cpp
pp = new T*[c]; // Columns as outer dimension
for (int i = 0; i // Instead of
#include // Instead of
using namespace std; // Add namespace declaration
```
- Use `int main()` instead of `void main()`[1]
- Add range checking for element access
- Implement move semantics (C++11+)
**5. Input/Output Stream Fixes**
Current `operator>>` incorrectly uses `const`:
```cpp
friend istream &operator>>(istream &stream, const Matrix &m);
```
**Fix:** Remove `const` qualifier:
```cpp
friend istream &operator>>(istream &stream, Matrix &m);
```
**6. Kronecker Product Indexing**
Current implementation uses reversed indices:
```cpp
m3.pp[m][n] = m1.pp[j] * m2.pp[k][l];
```
**Fix:** After correcting storage order:
```cpp
m3(m,n) = m1(i,j) * m2(k,l); // Using corrected operator()
```
**7. Memory Management Improvements**
- Use `std::vector` for automatic memory management:
```cpp
vector> data;
```
- Implement exception handling instead of `exit()`
- Add self-assignment check in `operator=`:
```cpp
if (this == &rhs) return *this;
```
**8. Additional Recommendations**
- Implement bounds checking with `at()` method
- Add `noexcept` specifiers where appropriate
- Use const-correctness consistently
- Implement missing operators (`-=`, `*=`, etc.)
- Consider expression templates for optimization
Example of corrected constructor:
```cpp
template
Matrix::Matrix(int r, int c) : rSize(r), cSize(c) {
if (r <= 0 || c <= 0) {
throw invalid_argument("Invalid matrix dimensions");
}
pp = new T*[r];
for (int i = 0; i < r; ++i) {
pp = new T[c](); // Zero-initialized
}
}
```
These changes would make the Matrix class safer, more maintainable, and compliant with modern C++ standards while preserving its
Citations:
[1] https://ppl-ai-file-upload.s3.amazonaws ... /paste.txt
---
Answer from Perplexity: pplx.ai/share
Exercise: Try other generative AI.