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This program for the first link is not compiling and it is hard to see where the sort is taking place. I will check the other link.
-- modified at 13:04 Monday 10th July, 2006
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Well the other link is for vector you need to customize it, i feel that we need to customize it for list.
sort void sort();<br />
Sorts the list elements in ascending order. The comparison operator < ("less than") must be defined for the list element type. Note that the STL sort algorithm does NOT work for lists; that's why a sort member function is supplied.<br />
nums.sort(); <br />
If we provide the < than operator for the struct its fine i guess.
Regards,
FarPointer
Blog:FARPOINTER
-- modified at 13:34 Monday 10th July, 2006
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Harold_Wishes wrote: This program for the first link is not compiling...
Why not? What compiler error are you receiving?
"The largest fire starts but with the smallest spark." - David Crow
"Judge not by the eye but by the heart." - Native American Proverb
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Well, I hate to place it here, but there were 14 errors.
C:\Documents and Settings\WoodallH\Desktop\C++\Project 6 Nesty tag\Sort.cpp(23) : error C2955: 'list' : use of class template requires template argument list
c:\program files\microsoft visual studio\vc98\include\list(415) : see declaration of 'list'
C:\Documents and Settings\WoodallH\Desktop\C++\Project 6 Nesty tag\Sort.cpp(23) : error C2133: 'mylist' : unknown size
C:\Documents and Settings\WoodallH\Desktop\C++\Project 6 Nesty tag\Sort.cpp(23) : error C2512: 'list' : no appropriate default constructor available
C:\Documents and Settings\WoodallH\Desktop\C++\Project 6 Nesty tag\Sort.cpp(23) : error C2262: 'mylist' : cannot be destroyed
C:\Documents and Settings\WoodallH\Desktop\C++\Project 6 Nesty tag\Sort.cpp(28) : error C2662: 'push_back' : cannot convert 'this' pointer from 'class std::list' to 'class std::list<_Ty,_A> &'
Reason: cannot convert from 'class std::list' to 'class std::list<_Ty,_A>'
Conversion requires a second user-defined-conversion operator or constructor
C:\Documents and Settings\WoodallH\Desktop\C++\Project 6 Nesty tag\Sort.cpp(30) : error C2662: 'push_back' : cannot convert 'this' pointer from 'class std::list' to 'class std::list<_Ty,_A> &'
Reason: cannot convert from 'class std::list' to 'class std::list<_Ty,_A>'
Conversion requires a second user-defined-conversion operator or constructor
C:\Documents and Settings\WoodallH\Desktop\C++\Project 6 Nesty tag\Sort.cpp(33) : error C2663: 'sort' : 2 overloads have no legal conversion for 'this' pointer
C:\Documents and Settings\WoodallH\Desktop\C++\Project 6 Nesty tag\Sort.cpp(36) : error C2955: 'list' : use of class template requires template argument list
c:\program files\microsoft visual studio\vc98\include\list(415) : see declaration of 'list'
C:\Documents and Settings\WoodallH\Desktop\C++\Project 6 Nesty tag\Sort.cpp(36) : error C2955: 'list' : use of class template requires template argument list
c:\program files\microsoft visual studio\vc98\include\list(415) : see declaration of 'list'
C:\Documents and Settings\WoodallH\Desktop\C++\Project 6 Nesty tag\Sort.cpp(36) : error C2663: 'begin' : 2 overloads have no legal conversion for 'this' pointer
C:\Documents and Settings\WoodallH\Desktop\C++\Project 6 Nesty tag\Sort.cpp(36) : error C2512: 'const_iterator' : no appropriate default constructor available
C:\Documents and Settings\WoodallH\Desktop\C++\Project 6 Nesty tag\Sort.cpp(36) : error C2262: 'citer' : cannot be destroyed
C:\Documents and Settings\WoodallH\Desktop\C++\Project 6 Nesty tag\Sort.cpp(37) : error C2663: 'end' : 2 overloads have no legal conversion for 'this' pointer
C:\Documents and Settings\WoodallH\Desktop\C++\Project 6 Nesty tag\Sort.cpp(39) : error C2228: left of '.m_iData' must have class/struct/union type
Error executing cl.exe.
Sort.exe - 14 error(s), 0 warning(s)
#include <list>
#include <string>
#include <iostream>
#include <algorithm>
using namespace std;
class MyData
{
public:
int m_iData;
string m_strSomeOtherData;
};
bool MyDataSortPredicate(const MyData& lhs, const MyData& rhs)
{
return lhs.m_iData < rhs.m_iData;
}
int main()
{
list mylist;
MyData data;
data.m_iData = 3;
mylist.push_back(data);
data.m_iData = 1;
mylist.push_back(data);
mylist.sort(MyDataSortPredicate);
for (list::const_iterator citer = mylist.begin();
citer != mylist.end(); ++citer)
{
cout << (*citer).m_iData << endl;
}
return 0;
}
-- modified at 13:48 Monday 10th July, 2006
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I still could not get it to run.
C:\Documents and Settings\WoodallH\Desktop\C++\Project 6 Nesty tag\Sort.cpp(33) : error C2664: 'void __thiscall std::list<class mydata,class="" std::allocator<class="" mydata=""> >::sort(struct std::greater<class mydata="">)' : cannot convert parameter 1 from '
bool (const class MyData &,const class MyData &)' to 'struct std::greater<class mydata="">'
No constructor could take the source type, or constructor overload resolution was ambiguous
C:\Documents and Settings\WoodallH\Desktop\C++\Project 6 Nesty tag\Sort.cpp(36) : error C2955: 'list' : use of class template requires template argument list
c:\program files\microsoft visual studio\vc98\include\list(415) : see declaration of 'list'
C:\Documents and Settings\WoodallH\Desktop\C++\Project 6 Nesty tag\Sort.cpp(36) : error C2955: 'list' : use of class template requires template argument list
c:\program files\microsoft visual studio\vc98\include\list(415) : see declaration of 'list'
C:\Documents and Settings\WoodallH\Desktop\C++\Project 6 Nesty tag\Sort.cpp(36) : error C2440: 'initializing' : cannot convert from 'class std::list<class mydata,class="" std::allocator<class="" mydata=""> >::iterator' to 'class std::list<_Ty,_A>::const_iter
ator'
No constructor could take the source type, or constructor overload resolution was ambiguous
C:\Documents and Settings\WoodallH\Desktop\C++\Project 6 Nesty tag\Sort.cpp(36) : error C2262: 'citer' : cannot be destroyed
C:\Documents and Settings\WoodallH\Desktop\C++\Project 6 Nesty tag\Sort.cpp(37) : error C2679: binary '!=' : no operator defined which takes a right-hand operand of type 'class std::list<class mydata,class="" std::allocator<class="" mydata=""> >::iterator' (
or there is no acceptable conversion)
C:\Documents and Settings\WoodallH\Desktop\C++\Project 6 Nesty tag\Sort.cpp(39) : error C2228: left of '.m_iData' must have class/struct/union type
Error executing cl.exe.
Sort.exe - 7 error(s), 0 warning(s)
#include <list>
#include <string>
#include <iostream>
#include <algorithm>
using namespace std;
class MyData
{
public:
int m_iData;
string m_strSomeOtherData;
};
bool MyDataSortPredicate(const MyData& lhs, const MyData& rhs)
{
return lhs.m_iData < rhs.m_iData;
}
int main()
{
list<MyData> mylist;
MyData data;
data.m_iData = 3;
mylist.push_back(data);
data.m_iData = 1;
mylist.push_back(data);
mylist.sort(MyDataSortPredicate);
for (list::const_iterator citer = mylist.begin();
citer != mylist.end(); ++citer)
{
cout << (*citer).m_iData << endl;
}
return 0;
}
-- modified at 14:21 Monday 10th July, 2006
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Change it in the for loop also .
Regards,
FarPointer
Blog:FARPOINTER
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I decided to pick this apart and comment out the for loop because it is still not obvious to me where the problem is. The for loop seems to declare a pointer and initialize it to point to the beginning of the list and simply prints each item on screen until the pointer reaches the end.
That aside I notice there appears to be some conversion type error in the line above with mylist.sort(MyDataSortPredicate); See error message below.
c:\Documents and Settings\WoodallH\Desktop\C++\Project 6 Nesty tag\Sort.cpp(33) : error C2664: 'void __thiscall std::list<class mydata,class="" std::allocator<class="" mydata=""> >::sort(struct std::greater<class mydata="">)' : cannot convert parameter 1 from '
bool (const class MyData &,const class MyData &)' to 'struct std::greater<class mydata="">'
No constructor could take the source type, or constructor overload resolution was ambiguous
Error executing cl.exe.
Sort.exe - 1 error(s), 0 warning(s)
mylist.sort(MyDataSortPredicate);
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See here for the STL fix.
"The largest fire starts but with the smallest spark." - David Crow
"Judge not by the eye but by the heart." - Native American Proverb
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Harold_Wishes wrote: // Dump the list to check the result
for (list::const_iterator citer = mylist.begin();
citer != mylist.end(); ++citer)
{
cout << (*citer).m_iData << endl;
}
Don't write your own loop for this.
void printData(const MyData& data)
{
cout << data.m_iData << endl;
}
for_each(myList.begin(), myList.end(), printData);
If you decide to become a software engineer, you are signing up to have a 1/2" piece of silicon tell you exactly how stupid you really are for 8 hours a day, 5 days a week
Zac
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This worked. But I still have commented out the code that is suppose to do the sort---> mylist.sort(MyDataSortPredicate);
C:\Documents and Settings\WoodallH\Desktop\C++\Project 6 Nesty tag\Sort.cpp(38) : error C2664: 'void __thiscall std::list<class MyData,class std::allocator<class MyData> >::sort(struct std::greater<class MyData>)' : cannot convert parameter 1 from '
bool (const class MyData &,const class MyData &)' to 'struct std::greater<class MyData>'
No constructor could take the source type, or constructor overload resolution was ambiguous
Error executing cl.exe.
-- modified at 15:03 Monday 10th July, 2006
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You can either use the general sort algorithm (std::sort ) or write a specialized less<MyData>() functor that looks something like:
struct std::less<MyData>
{
bool operator()(const MyData& lhs, const MyData& rhs)
{
return lhs.m_iData < rhs.m_iData;
}
};
And then call mylist.sort(std::less<MyData>) .
If you decide to become a software engineer, you are signing up to have a 1/2" piece of silicon tell you exactly how stupid you really are for 8 hours a day, 5 days a week
Zac
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Gotta watch those angle brackets:
void main( void )
{
list<MyData> mylist;
...
for (list<MyData>::const_iterator citer = mylist.begin();
}
"The largest fire starts but with the smallest spark." - David Crow
"Judge not by the eye but by the heart." - Native American Proverb
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how did u bring those mydata in-side the angular brackets .
and that horizontal slash in prev post.
Regards,
FarPointer
Blog:FARPOINTER
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FarPointer wrote: and that horizontal slash in prev post.
Horizontal rule.
"The largest fire starts but with the smallest spark." - David Crow
"Judge not by the eye but by the heart." - Native American Proverb
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The second link contains a good example. They are using the <vector> class. I am using the <list> class to store my list. I suppose I can use the vector example to implement what I am trying to do with the <list> class. I will have to think about this because I do not think items in lists can be accessed at random like vectors. Perhaps I am wrong on both accounts.
Regards again.
HRW
-- modified at 13:36 Monday 10th July, 2006
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try overiding the < operator of the struct.
Chosing between vector and list you need to be careful bcoz the vector reallocates the whole data on push_back if it doesnt has space to expand ,while list is a linked list .so u need to choose according to your ease.
just bcoz you cant do sort on it doesnt mean we have to drop it , you can also write sort from scratch.
Regards,
FarPointer
Blog:FARPOINTER
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Harold,
You'll do much better if you get (1) a copy of Stroustrup and (2) a copy of Josuttis. Read them in that order. Because what you want to do is trivial and will be explained by the first book; putting in the time for the second will be worth it.
earl
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Are these C++ authors of C++ books? I will look for them. I did not see anything in the Deitel & Deitel book that was too helpful.
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Hit up amazon for those two. Stroustrup largely invented C++ and wrote one of the definitive books on it; Josuttis wrote a book on the standard library that is a great complement to the former.
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I did check amazon and saw several books by Stroustrup. Do you know the title of the book?
-- modified at 21:13 Monday 10th July, 2006
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http://www.amazon.com/gp/product/0201700735/sr=8-1/qid=1152627803/ref=pd_bbs_1/002-6564248-4536802?ie=UTF8
http://www.amazon.com/gp/product/0201379260/002-6564248-4536802?n=283155
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Simply define an ordering by implementing operator < . i.e.
struct data
{
string Length;
string Sequence;
string N_Terminal;
string C_Terminal;
friend bool operator<(const data &L, const data &R)
{
return L.Sequence<R.Sequence;
}
};
g_DataList.sort();
Steve
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So after creating the list, doesn't the sort function take in one parameter of type data? And will the list be printed in sorted order after the sort function is invoked?
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