ne peut pas déclarer la variable 'test' pour être de type abstrait 'OurStack <int>'

Question

J'ai regardé des réponses similaires et ils avaient tous les paramètres faux ou fautes de frappe.

J'essaye de créer une pile de type int, mais j'ai des problèmes avec la fonction push.

L'erreur exacte est:

OurStack<int> test; 
      ^
In file included from StackTester.cpp:5:0: 
OurStack.h:7:7: note: because the following virtual functions are pure within 'OurStack<int>': 
class OurStack : public StackInterface<T> 
    ^
In file included from OurStack.h:4:0, 
       from StackTester.cpp:5: 
StackInterface.h:11:15: note: bool StackInterface<T>::push(const T&) [with T = int] 
    virtual bool push(const T& newEntry) = 0; 

Voici mon code:

StackInterface.h

/** @file StackInterface.h */ 
#ifndef _STACK_INTERFACE 
#define _STACK_INTERFACE 
template<class T> class StackInterface 
{ public: 

    /** Sees whether this stack is empty. @return True if the stack is empty, or false if not. */ 
virtual bool isEmpty() const = 0; 

/** Adds a new entry to the top of this stack. @post If the operation was successful, newEntry is at the top of the stack. @param newEntry The object to be added as a new entry. @return True if the addition is successful or false if not. */ 
virtual bool push(const T& newEntry) = 0; 

/** Removes the top of this stack. @post If the operation was successful, the top of the stack has been removed. @return True if the removal is successful or false if not. */ 
virtual bool pop() = 0; 

/** Returns the top of this stack. @pre The stack is not empty. @post The top of the stack has been returned, and the stack is unchanged. @return The top of the stack. */ 
virtual T peek() const = 0; 
}; 

// end StackInterface 
#endif 

OurStack.h

#ifndef _STACK_H_ 
#define _STACK_H_ 

#include "StackInterface.h" 

template <class T> 
class OurStack : public StackInterface<T> 
{ 
    private: 
    std::stack<T> ourStack; 

    public: 
     OurStack(); 
     bool isEmpty() const; 
     bool push(const T& newEntry) const; 
     bool pop(); 
     T peek() const; 

}; 
#include "OurStack.cpp" 
#endif 

OurStack.cpp

#include "OurStack.h" 

template <class T> 
OurStack<T>::OurStack() 
{ 
    //not much to do between these 
} 

template <class T> 
bool OurStack<T>::isEmpty() const 
{ 
    return ourStack.empty(); 
} 

template <class T> 
bool OurStack<T>::push(const T& newEntry) const 
{ 
    ourStack.push(&newEntry); 
    return true; 
} 

template <class T> 
bool OurStack<T>::pop() 
{ 
    if(ourStack.empty() == true) 
     return false; 
    else 
    { 
     ourStack.pop(); 
     return true; 
    } 
} 

template <class T> 
T OurStack<T>::peek() const 
{ 
    return ourStack.top(); 
} 

StackTester.cpp

#include <iostream> 
#include <cstdlib> 
#include <string> 
#include <stack> 
#include "OurStack.h" 

using namespace std; 

OurStack<int> test; 
int any; 

int main() 
{ 
    cout<<"press any number"; 
    cin>>any; 
    return 0; 
} 

Answer 1

Vous déclarez bool OurStack<T>::push(const T& newEntry) const; mais votre classe de base Déclare bool push(const T& newEntry);. push n'est pas const. Utilisez le mot-clé override pour éviter ces problèmes.

Answer 2

Comment une fonction push:

bool push(const T& newEntry) const; 

peut-être const?

En outre, les noms comme celui-ci:

_STACK_H_ 

sont réservés à la mise en œuvre. utilisez simplement:

STACK_H