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Create an unordered_map with custom object as key

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0

I want to create an std::unordered_map with Node as the key. I have already overloaded the operator == and <. I have also defined a hash function. However, it is giving me error:

C2280: std::hash<_Kty>::hash(const std::hash<_Kty> &): attempting to reference a deleted function

Here is my code for the Node class:

#include "Node.h"

Node::Node() 
 word = Word();


Node::Node(Word input_word) : word(input_word) 

Node::Node(const Node& other) 
 word = other.word;
 connection = other.connection;


Node::~Node() 


bool Node::operator<(const Node& other) 
 return (word < other.get_word());


bool Node::operator==(const Node& other) 
 if (word == other.word) 
 if (connection.size() == other.connection.size()) 
 for (unsigned int i = 0; i < connection.size(); i++) 
 if (connection[i] != other.connection[i]) 
 return false;
 
 
 return true;
 else 
 return false;
 
 else 
 return false;
 


Word Node::get_word() const 
 return word;


int Node::add_connection(Edge* input_node) 
 connection.push_back(input_node);
 return SUCCESS;


vector<Edge*> Node::retrieve_connection() const
 return connection;



namespace std 
 template <> struct hash<Node> 
 size_t operator()(const Node& other) const 
 return hash<string>()(other.get_word().get_string()) ^
 hash<int>()(other.retrieve_connection().size());
 
 ;

I am very confused about what I should add next. I have tried most suggestions that I can find on websites, but none of them works.

Thank you for your attention!

c++ hash unordered-map

share|improve this question

edited Mar 23 at 5:14

melpomene

63.7k55195

asked Mar 23 at 4:21

Runsheng MaRunsheng Ma

13

• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  
  Please post a Minimal, Complete, and Verifiable example and the complete error messages from the compiler.
  
  – R Sahu
  Mar 23 at 4:39
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  "I have tried most suggestions that I can find on websites, but none of them works." It's hard for us to help you when we can't try suggestions, get error messages with our preferred compiler, simplify the code to see if the error goes away, and so on.
  
  – David Schwartz
  Mar 23 at 5:20
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  I had to make a lot of assumptions about your Node and Word classes (many of them bad coding style; e.g. you should use = default for constructors and destructors when possible, or in this case just use the Rule of Zero and don't explicitly define them at all), but when I did everything compiled perfectly. Please share the full error message and see if you can provide a complete (non-)working minimal example.
  
  – Daniel H
  Mar 23 at 5:21
  

  
  
  
  

add a comment | 

0

I want to create an std::unordered_map with Node as the key. I have already overloaded the operator == and <. I have also defined a hash function. However, it is giving me error:

C2280: std::hash<_Kty>::hash(const std::hash<_Kty> &): attempting to reference a deleted function

Here is my code for the Node class:

#include "Node.h"

Node::Node() 
 word = Word();


Node::Node(Word input_word) : word(input_word) 

Node::Node(const Node& other) 
 word = other.word;
 connection = other.connection;


Node::~Node() 


bool Node::operator<(const Node& other) 
 return (word < other.get_word());


bool Node::operator==(const Node& other) 
 if (word == other.word) 
 if (connection.size() == other.connection.size()) 
 for (unsigned int i = 0; i < connection.size(); i++) 
 if (connection[i] != other.connection[i]) 
 return false;
 
 
 return true;
 else 
 return false;
 
 else 
 return false;
 


Word Node::get_word() const 
 return word;


int Node::add_connection(Edge* input_node) 
 connection.push_back(input_node);
 return SUCCESS;


vector<Edge*> Node::retrieve_connection() const
 return connection;



namespace std 
 template <> struct hash<Node> 
 size_t operator()(const Node& other) const 
 return hash<string>()(other.get_word().get_string()) ^
 hash<int>()(other.retrieve_connection().size());
 
 ;

I am very confused about what I should add next. I have tried most suggestions that I can find on websites, but none of them works.

Thank you for your attention!

c++ hash unordered-map

share|improve this question

edited Mar 23 at 5:14

melpomene

63.7k55195

asked Mar 23 at 4:21

Runsheng MaRunsheng Ma

13

• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  
  Please post a Minimal, Complete, and Verifiable example and the complete error messages from the compiler.
  
  – R Sahu
  Mar 23 at 4:39
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  "I have tried most suggestions that I can find on websites, but none of them works." It's hard for us to help you when we can't try suggestions, get error messages with our preferred compiler, simplify the code to see if the error goes away, and so on.
  
  – David Schwartz
  Mar 23 at 5:20
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  I had to make a lot of assumptions about your Node and Word classes (many of them bad coding style; e.g. you should use = default for constructors and destructors when possible, or in this case just use the Rule of Zero and don't explicitly define them at all), but when I did everything compiled perfectly. Please share the full error message and see if you can provide a complete (non-)working minimal example.
  
  – Daniel H
  Mar 23 at 5:21
  

  
  
  
  

add a comment | 

I want to create an std::unordered_map with Node as the key. I have already overloaded the operator == and <. I have also defined a hash function. However, it is giving me error:

C2280: std::hash<_Kty>::hash(const std::hash<_Kty> &): attempting to reference a deleted function

Here is my code for the Node class:

#include "Node.h"

Node::Node() 
 word = Word();


Node::Node(Word input_word) : word(input_word) 

Node::Node(const Node& other) 
 word = other.word;
 connection = other.connection;


Node::~Node() 


bool Node::operator<(const Node& other) 
 return (word < other.get_word());


bool Node::operator==(const Node& other) 
 if (word == other.word) 
 if (connection.size() == other.connection.size()) 
 for (unsigned int i = 0; i < connection.size(); i++) 
 if (connection[i] != other.connection[i]) 
 return false;
 
 
 return true;
 else 
 return false;
 
 else 
 return false;
 


Word Node::get_word() const 
 return word;


int Node::add_connection(Edge* input_node) 
 connection.push_back(input_node);
 return SUCCESS;


vector<Edge*> Node::retrieve_connection() const
 return connection;



namespace std 
 template <> struct hash<Node> 
 size_t operator()(const Node& other) const 
 return hash<string>()(other.get_word().get_string()) ^
 hash<int>()(other.retrieve_connection().size());
 
 ;

I am very confused about what I should add next. I have tried most suggestions that I can find on websites, but none of them works.

Thank you for your attention!

c++ hash unordered-map

share|improve this question

edited Mar 23 at 5:14

melpomene

63.7k55195

asked Mar 23 at 4:21

Runsheng MaRunsheng Ma

13

#include "Node.h"

Node::Node() 
 word = Word();


Node::Node(Word input_word) : word(input_word) 

Node::Node(const Node& other) 
 word = other.word;
 connection = other.connection;


Node::~Node() 


bool Node::operator<(const Node& other) 
 return (word < other.get_word());


bool Node::operator==(const Node& other) 
 if (word == other.word) 
 if (connection.size() == other.connection.size()) 
 for (unsigned int i = 0; i < connection.size(); i++) 
 if (connection[i] != other.connection[i]) 
 return false;
 
 
 return true;
 else 
 return false;
 
 else 
 return false;
 


Word Node::get_word() const 
 return word;


int Node::add_connection(Edge* input_node) 
 connection.push_back(input_node);
 return SUCCESS;


vector<Edge*> Node::retrieve_connection() const
 return connection;



namespace std 
 template <> struct hash<Node> 
 size_t operator()(const Node& other) const 
 return hash<string>()(other.get_word().get_string()) ^
 hash<int>()(other.retrieve_connection().size());
 
 ;

share|improve this question

edited Mar 23 at 5:14

melpomene

63.7k55195

asked Mar 23 at 4:21

Runsheng MaRunsheng Ma

13

share|improve this question

edited Mar 23 at 5:14

melpomene

63.7k55195

asked Mar 23 at 4:21

Runsheng MaRunsheng Ma

13

edited Mar 23 at 5:14

melpomene

63.7k55195

edited Mar 23 at 5:14

melpomene

63.7k55195

asked Mar 23 at 4:21

Runsheng MaRunsheng Ma

13

asked Mar 23 at 4:21

Runsheng MaRunsheng Ma

13