Nested Boost::unordered_map with std::pair insertion help ..

Newsgroup: comp.lang.c++

Subject: Nested Boost::unordered_map with std::pair insertion help ..

From: Rahul Mathur <srivmuk@...>

Date: Thu, 20 Feb 2014 04:32:58 -0800 (PST)



All,



I have having Boost boost::unordered_map nested map calling boost::unordered_map which calls std::map finally.



The LHS (towards RHS) side key for first boost::unordered_map is 'int' type followed by next key being char buffer value of size 10, and key for std::map being again a char buffer value of size 10. So the boost::unordered_map has nested map internally.

I have to insert the char buffer of size 10 (value being either 'ORANGE' or ORD123 as test case) into nested std::pair as defined below. After inserting, I have to search or find the value from char buffer of size 10.



The code as compiled on Linux is -



----

#include <cstdio>

#include <cstdlib>

#include <iostream>

#include <boost/unordered_map.hpp>

#include <map>

#include <algorithm>

#include <string>



using namespace std;



#if 0

#pragma pack(push, 2)

struct BookKeeping {

int ABCD;

char Apple_ID [10];

char Apple_NAME[10];

int Price;

int Number;

};

#pragma pack(pop)

#endif



class Name { // buffer of size 10

char str[10];

public:

Name() {

strcpy(str, "");

}

Name(char *s) {

strcpy(str, s);

}

char *get() {

return str;

}

};



bool operator<(Name a, Name b)

{

return strcmp(a.get(), b.get()) < 0;

}



#pragma pack(push, 2)

struct BookKeeping {

int ABCD;

Name Apple_ID;

Name Apple_NAME;

int Price;

int Number;

};

#pragma pack(pop)



BookKeeping *_bkkping;



typedef boost::unordered_map< int, boost::unordered_map< Name, std::map< Name, int > > > _uordmap; // nested boost::unordered_map



class BkKping {

private:

_uordmap * uordmap;



typedef boost::unordered_map< int, boost::unordered_map< Name, std::map< Name, int > > >::iterator _itr_1;

typedef boost::unordered_map< Name, std::map< Name, int > >::iterator _itr_2;

typedef std::map< Name, int >::iterator _itr_3;



public:

BkKping () {

uordmap = new _uordmap ();

}

void Apple ( int abcd, const char * Apple_ID_, const char * Color_, int Price_ );

~BkKping () {

delete uordmap;

}



};



void BkKping::Apple ( int abcd, const char * Apple_ID_, const char * Color_, int Price_ ) {



uordmap->insert( std::pair< int, std::pair< Name, std::pair< Name, BookKeeping &> > > ( _bkkping->ABCD , _bkkping->Apple_ID, _bkkping->Apple_NAME, *_bkkping) ); // nested std::pair<> insertion

}



int main () {



int abcd;

const char * Apple_ID_;

const char * Color_;

int Price_;



BkKping book;

book.Apple( abcd, Apple_ID_, Color_, Price_);



}

-----



The error message is -



---

hello.cpp: In member function âvoid BkKping::Apple(int, const char*, const char*, int)â:

hello.cpp:76: error: no matching function for call to âstd::pair<int, std::pair<Name, std::pair<Name, BookKeeping&> > >::pair(int&, Name&, Name&, BookKeeping&)â

/usr/lib/gcc/x86_64-redhat-linux/4.4.6/../../../../include/c++/4.4.6/bits/stl_pair.h:83: note: candidates are: std::pair<_T1, _T2>::pair(const _T1&, const _T2&) [with _T1 = int, _T2 = std::pair<Name, std::pair<Name, BookKeeping&> >]

/usr/lib/gcc/x86_64-redhat-linux/4.4.6/../../../../include/c++/4.4.6/bits/stl_pair.h:79: note: std::pair<_T1, _T2>::pair() [with _T1 = int, _T2 = std::pair<Name, std::pair<Name, BookKeeping&> >]

/usr/lib/gcc/x86_64-redhat-linux/4.4.6/../../../../include/c++/4.4.6/bits/stl_pair.h:68: note: std::pair<int, std::pair<Name, std::pair<Name, BookKeeping&> > >::pair(const std::pair<int, std::pair<Name, std::pair<Name, BookKeeping&> > >&)

--



I have created a class buffer to read size 10.



Please help.



P.S: No issue with Boost compilation, simply looking for proper semantic call for nested std::pair<>.

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