473,325 Members | 2,342 Online
Bytes | Software Development & Data Engineering Community
Post Job

Home Posts Topics Members FAQ

Join Bytes to post your question to a community of 473,325 software developers and data experts.

can not reference make_pair?

Hi,
I have this code piece,

vector<int> v1, v2;
vector<pair<int, int> > uups;
....

transform(v1.begin(), v1.end(), v2.begin(), uups.end(),
ptr_fun(make_pair));

But my gcc compiler complains that "no matching function for call to
`ptr_fun(<unknown type>". Do you know what's wrong here?

Thanks.
Jul 22 '05 #1
2 2323

"John Black" <bl***@eed.com> wrote in message
news:cn*********@cliff.xsj.xilinx.com...
Hi,
I have this code piece,

vector<int> v1, v2;
vector<pair<int, int> > uups;
....

transform(v1.begin(), v1.end(), v2.begin(), uups.end(),
ptr_fun(make_pair));
std::make_pair is a function template; to retrieve a function pointer to one of
its specializations you must use a cast or assign it to a function pointer
variable, as in the following:

#include <algorithm>
#include <functional>
#include <utility>
#include <vector>

using namespace std;

int main()
{
pair<int, int> (*make_int_pair) (int, int) = make_pair;

vector<int> v1, v2;
vector<pair<int, int> > uups;
transform(v1.begin(), v1.end(), v2.begin(), uups.end(),
ptr_fun(make_int_pair));
}

One more thing: I'm not sure the standard guarantees that make_pair doesn't have
additional function parameters with default values. Probably someone else here
knows.
Thanks.


Jonathan
Jul 22 '05 #2
"John Black" <bl***@eed.com> wrote in message
news:cn*********@cliff.xsj.xilinx.com...
Hi,
I have this code piece,

vector<int> v1, v2;
vector<pair<int, int> > uups;
....

transform(v1.begin(), v1.end(), v2.begin(), uups.end(),
ptr_fun(make_pair));

But my gcc compiler complains that "no matching function for call to
`ptr_fun(<unknown type>". Do you know what's wrong here?

Thanks.


make_pair is not a function, just a template. But make_pair<int, int> is.
One more thing: you must "push_back" the result into uups, not just
placing it at the end.

transform(v1.begin(), v1.end(), v2.begin(), back_inserter(uups),
ptr_fun(make_pair<int, int>));

--
ES Kim
Jul 22 '05 #3

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

3
by: JustSomeGuy | last post by:
in the stl map class I see the use of a function pair and make_pair. What is the difference between pair and make_pair? dictionary.insert(std::pair<Key, Value>(k,v)); works as well as: ...
3
by: lallous | last post by:
Hello Given this: map<int, mystruct> m; m = item; item.id++; m = item; How can I get a direct refrence to the location of the just inserted item?
10
by: Jim Langston | last post by:
Expected output of program: Key is: 0 String is: Hello Key is: 1 String is: Goodbye Key is: 2 String is: The end Actual output: Key is: 0 String is: The End Key is: 1 String is: Key is: 2...
2
by: Markus Dehmann | last post by:
I am trying to make a pair with a string and an auto_ptr: #include <iostream> #include <map> using namespace std; int main(){ auto_ptr<intp(new int(3)); make_pair("x",p); }
4
by: Michael Holm | last post by:
Calling the function "float dist = Splines.Pick(Vector2(x,y), 5.0f, type, &point);" The function is now defined as float BSpline::Pick(Vector2Coord, float radius, ePickType &type, Vector3...
4
by: Juha Nieminen | last post by:
Is there any online C++ library reference containing all the functions and types in the standard C++ library? A quick google search gives C++ references alright, but they all seem to be quite...
3
by: subramanian100in | last post by:
Given two types T1 and T2, we can create pair<T1, T2p(value1, value2); where value1 and value2 are of types T1 and T2 respectively. Suppose we want to assign a new pair<value to p. We can do...
2
by: puzzlecracker | last post by:
Does map copy the object, both key and value during the insert? is this example correct: std::map<std::string Tmy_map; template<typename T> void foo(const std::string str, const T & t){...
275
by: Astley Le Jasper | last post by:
Sorry for the numpty question ... How do you find the reference name of an object? So if i have this bob = modulename.objectname() how do i find that the name is 'bob'
0
by: ryjfgjl | last post by:
ExcelToDatabase: batch import excel into database automatically...
1
isladogs
by: isladogs | last post by:
The next Access Europe meeting will be on Wednesday 6 Mar 2024 starting at 18:00 UK time (6PM UTC) and finishing at about 19:15 (7.15PM). In this month's session, we are pleased to welcome back...
0
by: Vimpel783 | last post by:
Hello! Guys, I found this code on the Internet, but I need to modify it a little. It works well, the problem is this: Data is sent from only one cell, in this case B5, but it is necessary that data...
0
by: jfyes | last post by:
As a hardware engineer, after seeing that CEIWEI recently released a new tool for Modbus RTU Over TCP/UDP filtering and monitoring, I actively went to its official website to take a look. It turned...
0
by: ArrayDB | last post by:
The error message I've encountered is; ERROR:root:Error generating model response: exception: access violation writing 0x0000000000005140, which seems to be indicative of an access violation...
1
by: PapaRatzi | last post by:
Hello, I am teaching myself MS Access forms design and Visual Basic. I've created a table to capture a list of Top 30 singles and forms to capture new entries. The final step is a form (unbound)...
1
by: Shællîpôpï 09 | last post by:
If u are using a keypad phone, how do u turn on JavaScript, to access features like WhatsApp, Facebook, Instagram....
0
by: af34tf | last post by:
Hi Guys, I have a domain whose name is BytesLimited.com, and I want to sell it. Does anyone know about platforms that allow me to list my domain in auction for free. Thank you
0
by: Faith0G | last post by:
I am starting a new it consulting business and it's been a while since I setup a new website. Is wordpress still the best web based software for hosting a 5 page website? The webpages will be...

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.