C++ how to use emplace_back for user defined structure
1
I am trying to make use of emplace_back for my user defined structure:
#include <cstdint>
#include <vector>
#include <string>
struct IDNumber
{
IDNumber(std::vector<int> d) : id(d){}
std::vector<int> id;
};
struct Def
{
Def(std::initializer_list<int> id) : mid(id){}
IDNumber mid;
};
struct Student
{
std::vector<Def> ent;
};
int main()
{
Student a;
a.ent.emplace_back({ {2000} });
}
I get compilation issues:
error: no matching function for call to 'std::vector<EntryDef>::emplace_back'
c++ c++11
asked Nov 14 '18 at 14:35
ProgrammerProgrammer
2,9201851103
add a comment |
1
I am trying to make use of emplace_back for my user defined structure:
#include <cstdint>
#include <vector>
#include <string>
struct IDNumber
{
IDNumber(std::vector<int> d) : id(d){}
std::vector<int> id;
};
struct Def
{
Def(std::initializer_list<int> id) : mid(id){}
IDNumber mid;
};
struct Student
{
std::vector<Def> ent;
};
int main()
{
Student a;
a.ent.emplace_back({ {2000} });
}
I get compilation issues:
error: no matching function for call to 'std::vector<EntryDef>::emplace_back'
c++ c++11
asked Nov 14 '18 at 14:35
ProgrammerProgrammer
2,9201851103
5
Your first argument to your constructor isstd::initializer_list<int>yet you pass{ {2}, 1 }?
– CoryKramer
Nov 14 '18 at 14:38
I tried to change the line - a.ent.emplace_back({2,1,2}, FType::FD_NONE, Fmt::FMT_NONE, RWProp::PROP_RO, FId(0,TTypes::TYPE_NONE)); - but still I get the compilation issue - am I missing something?
– Programmer
Nov 14 '18 at 14:41
4
emplace_backis function template which tries to deduce the types of arguments. an initializer list does not have a type, so deduction fails. Usestd::initializer_list<int>{ 2, 1 }.
– Piotr Skotnicki
Nov 14 '18 at 14:42
@CoryKramer what is wrong with list-initializing the first int?
– Piotr Skotnicki
Nov 14 '18 at 14:44
@PiotrSkotnicki yeah, they kind of messed upinitializer_list
– bolov
Nov 14 '18 at 15:00
add a comment |
1
1
1
I am trying to make use of emplace_back for my user defined structure:
#include <cstdint>
#include <vector>
#include <string>
struct IDNumber
{
IDNumber(std::vector<int> d) : id(d){}
std::vector<int> id;
};
struct Def
{
Def(std::initializer_list<int> id) : mid(id){}
IDNumber mid;
};
struct Student
{
std::vector<Def> ent;
};
int main()
{
Student a;
a.ent.emplace_back({ {2000} });
}
I get compilation issues:
error: no matching function for call to 'std::vector<EntryDef>::emplace_back'
c++ c++11
asked Nov 14 '18 at 14:35
ProgrammerProgrammer
2,9201851103
I am trying to make use of emplace_back for my user defined structure:
#include <cstdint>
#include <vector>
#include <string>
struct IDNumber
{
IDNumber(std::vector<int> d) : id(d){}
std::vector<int> id;
};
struct Def
{
Def(std::initializer_list<int> id) : mid(id){}
IDNumber mid;
};
struct Student
{
std::vector<Def> ent;
};
int main()
{
Student a;
a.ent.emplace_back({ {2000} });
}
I get compilation issues:
error: no matching function for call to 'std::vector<EntryDef>::emplace_back'
c++ c++11
c++ c++11
asked Nov 14 '18 at 14:35
ProgrammerProgrammer
2,9201851103
asked Nov 14 '18 at 14:35
ProgrammerProgrammer
2,9201851103
edited Nov 15 '18 at 0:48
Programmer
asked Nov 14 '18 at 14:35
ProgrammerProgrammer
2,9201851103
asked Nov 14 '18 at 14:35
ProgrammerProgrammer
2,9201851103
asked Nov 14 '18 at 14:35
ProgrammerProgrammer
2,9201851103
2,9201851103
5
Your first argument to your constructor isstd::initializer_list<int>yet you pass{ {2}, 1 }?
– CoryKramer
Nov 14 '18 at 14:38
I tried to change the line - a.ent.emplace_back({2,1,2}, FType::FD_NONE, Fmt::FMT_NONE, RWProp::PROP_RO, FId(0,TTypes::TYPE_NONE)); - but still I get the compilation issue - am I missing something?
– Programmer
Nov 14 '18 at 14:41
4
emplace_backis function template which tries to deduce the types of arguments. an initializer list does not have a type, so deduction fails. Usestd::initializer_list<int>{ 2, 1 }.
– Piotr Skotnicki
Nov 14 '18 at 14:42
@CoryKramer what is wrong with list-initializing the first int?
– Piotr Skotnicki
Nov 14 '18 at 14:44
@PiotrSkotnicki yeah, they kind of messed upinitializer_list
– bolov
Nov 14 '18 at 15:00
add a comment |
5
Your first argument to your constructor isstd::initializer_list<int>yet you pass{ {2}, 1 }?
– CoryKramer
Nov 14 '18 at 14:38
I tried to change the line - a.ent.emplace_back({2,1,2}, FType::FD_NONE, Fmt::FMT_NONE, RWProp::PROP_RO, FId(0,TTypes::TYPE_NONE)); - but still I get the compilation issue - am I missing something?
– Programmer
Nov 14 '18 at 14:41
4
emplace_backis function template which tries to deduce the types of arguments. an initializer list does not have a type, so deduction fails. Usestd::initializer_list<int>{ 2, 1 }.
– Piotr Skotnicki
Nov 14 '18 at 14:42
@CoryKramer what is wrong with list-initializing the first int?
– Piotr Skotnicki
Nov 14 '18 at 14:44
@PiotrSkotnicki yeah, they kind of messed upinitializer_list
– bolov
Nov 14 '18 at 15:00
5
5
Your first argument to your constructor is
std::initializer_list<int> yet you pass { {2}, 1 }?– CoryKramer
Nov 14 '18 at 14:38
Your first argument to your constructor is
std::initializer_list<int> yet you pass { {2}, 1 }?– CoryKramer
Nov 14 '18 at 14:38
I tried to change the line - a.ent.emplace_back({2,1,2}, FType::FD_NONE, Fmt::FMT_NONE, RWProp::PROP_RO, FId(0,TTypes::TYPE_NONE)); - but still I get the compilation issue - am I missing something?
– Programmer
Nov 14 '18 at 14:41
I tried to change the line - a.ent.emplace_back({2,1,2}, FType::FD_NONE, Fmt::FMT_NONE, RWProp::PROP_RO, FId(0,TTypes::TYPE_NONE)); - but still I get the compilation issue - am I missing something?
– Programmer
Nov 14 '18 at 14:41
4
4
emplace_back is function template which tries to deduce the types of arguments. an initializer list does not have a type, so deduction fails. Use std::initializer_list<int>{ 2, 1 }.– Piotr Skotnicki
Nov 14 '18 at 14:42
emplace_back is function template which tries to deduce the types of arguments. an initializer list does not have a type, so deduction fails. Use std::initializer_list<int>{ 2, 1 }.– Piotr Skotnicki
Nov 14 '18 at 14:42
@CoryKramer what is wrong with list-initializing the first int?
– Piotr Skotnicki
Nov 14 '18 at 14:44
@CoryKramer what is wrong with list-initializing the first int?
– Piotr Skotnicki
Nov 14 '18 at 14:44
@PiotrSkotnicki yeah, they kind of messed up
initializer_list– bolov
Nov 14 '18 at 15:00
@PiotrSkotnicki yeah, they kind of messed up
initializer_list– bolov
Nov 14 '18 at 15:00
add a comment |
1 Answer
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The comment by @PiotrSkotnicki:
emplace_backis function template which tries to deduce the types of arguments. an initializer list does not have a type, so deduction fails.
Clarifies the problem.
An alternative way to "fix" this issue is to pass an rvalue of the needed type as argument of the constructor, instead of the initializer list:
EntryDef(ID &&id, FType ft, … ) : mid(std::forward<ID>(id)), ftype(ft), … {}
Called as:
Def a;
a.ent.emplace_back(ID{ 2, 1 }, FType::FD_NONE, …);
Live example HERE.
answered Nov 14 '18 at 16:13
Bob__Bob__
4,89331425
add a comment |
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The comment by @PiotrSkotnicki:
emplace_backis function template which tries to deduce the types of arguments. an initializer list does not have a type, so deduction fails.
Clarifies the problem.
An alternative way to "fix" this issue is to pass an rvalue of the needed type as argument of the constructor, instead of the initializer list:
EntryDef(ID &&id, FType ft, … ) : mid(std::forward<ID>(id)), ftype(ft), … {}
Called as:
Def a;
a.ent.emplace_back(ID{ 2, 1 }, FType::FD_NONE, …);
Live example HERE.
answered Nov 14 '18 at 16:13
Bob__Bob__
4,89331425
add a comment |
1
The comment by @PiotrSkotnicki:
emplace_backis function template which tries to deduce the types of arguments. an initializer list does not have a type, so deduction fails.
Clarifies the problem.
An alternative way to "fix" this issue is to pass an rvalue of the needed type as argument of the constructor, instead of the initializer list:
EntryDef(ID &&id, FType ft, … ) : mid(std::forward<ID>(id)), ftype(ft), … {}
Called as:
Def a;
a.ent.emplace_back(ID{ 2, 1 }, FType::FD_NONE, …);
Live example HERE.
answered Nov 14 '18 at 16:13
Bob__Bob__
4,89331425
add a comment |
1
1
1
The comment by @PiotrSkotnicki:
emplace_backis function template which tries to deduce the types of arguments. an initializer list does not have a type, so deduction fails.
Clarifies the problem.
An alternative way to "fix" this issue is to pass an rvalue of the needed type as argument of the constructor, instead of the initializer list:
EntryDef(ID &&id, FType ft, … ) : mid(std::forward<ID>(id)), ftype(ft), … {}
Called as:
Def a;
a.ent.emplace_back(ID{ 2, 1 }, FType::FD_NONE, …);
Live example HERE.
answered Nov 14 '18 at 16:13
Bob__Bob__
4,89331425
The comment by @PiotrSkotnicki:
emplace_backis function template which tries to deduce the types of arguments. an initializer list does not have a type, so deduction fails.
Clarifies the problem.
An alternative way to "fix" this issue is to pass an rvalue of the needed type as argument of the constructor, instead of the initializer list:
EntryDef(ID &&id, FType ft, … ) : mid(std::forward<ID>(id)), ftype(ft), … {}
Called as:
Def a;
a.ent.emplace_back(ID{ 2, 1 }, FType::FD_NONE, …);
Live example HERE.
answered Nov 14 '18 at 16:13
Bob__Bob__
4,89331425
answered Nov 14 '18 at 16:13
Bob__Bob__
4,89331425
answered Nov 14 '18 at 16:13
Bob__Bob__
4,89331425
answered Nov 14 '18 at 16:13
Bob__Bob__
4,89331425
4,89331425
add a comment |
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5
Your first argument to your constructor is
std::initializer_list<int>yet you pass{ {2}, 1 }?– CoryKramer
Nov 14 '18 at 14:38
I tried to change the line - a.ent.emplace_back({2,1,2}, FType::FD_NONE, Fmt::FMT_NONE, RWProp::PROP_RO, FId(0,TTypes::TYPE_NONE)); - but still I get the compilation issue - am I missing something?
– Programmer
Nov 14 '18 at 14:41
4
emplace_backis function template which tries to deduce the types of arguments. an initializer list does not have a type, so deduction fails. Usestd::initializer_list<int>{ 2, 1 }.– Piotr Skotnicki
Nov 14 '18 at 14:42
@CoryKramer what is wrong with list-initializing the first int?
– Piotr Skotnicki
Nov 14 '18 at 14:44
@PiotrSkotnicki yeah, they kind of messed up
initializer_list– bolov
Nov 14 '18 at 15:00