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gcc version 4.4.6 compiles code successfully. But gcc version 4.8.1 gives compile error.

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#include <iostream>

using namespace std;

class AbstractHashSet
{
    protected :
    int size;
    float load_factor;
    int current_limit;
    public :
    AbstractHashSet() : size(0), load_factor(0.75), current_limit(0){}
    int getSize(void) const { return size; }
    bool isEmpty(void) const { return size == 0; }
    float getLoadFactor(void) const {   return load_factor; }
    int getCapacity(void) const { return current_limit; }
    static int get_preferred_size(int n);
};

template<class KEY>
struct HashSetBaseElement
{
    KEY key;
    HashSetBaseElement *next;
    HashSetBaseElement(KEY k) : key(k),next(NULL){}
    virtual ~HashSetBaseElement(){}
};

template<class KEY>
class HashSetBase : public AbstractHashSet
{
    public :
    bool contains(KEY key)
    {
        if (size == 0) return false;
        return get_element(key) != NULL;
    }
    protected :
    HashSetBaseElement<KEY> *get_element(KEY key)
    {
        return NULL;
    }
};

template<class KEY>
class HashSet : public HashSetBase<KEY>
{
    public :
    HashSet(int n = 10)
    {
        HashSetBase<KEY>::setCapacity(n);
    }
    bool add(KEY key)
    {
        HashSetBaseElement<KEY> *e = get_element(key);
        if (e) return false;
        e =  new HashSetBaseElement<KEY>(key);
        return true;
    }
};
template<class KEY_T, class VALUE_T>
class HashMap : public HashSetBase<KEY_T>
{
    protected :
    struct Entry : public HashSetBaseElement<KEY_T>
    {
        VALUE_T value;
        Entry(KEY_T key, VALUE_T value) : HashSetBaseElement<KEY_T>(key), value(value){}
    };
    VALUE_T empty_value;

    public:
    VALUE_T &get(KEY_T key)
        {
            Entry *e = (Entry*)get_element(key);
            if (e) return e->value;
            return empty_value;
        }       
};

    struct Space
        {
            friend bool operator<(const Space &a, const Space &b)   
            {   return true;    }
            friend bool operator>(const Space &a, const Space &b)   
            {   return true;    }
        };
int main()
{    
    HashMap<int,Space*> pos_map;
    pos_map.get(100);
    cout<<"Hello World";

    return 0;
}

Compile error:

Error(s): source_file.cpp: In instantiation of ‘VALUE_T& HashMap::get(KEY_T) [with KEY_T = int; VALUE_T = Space*]’:source_file.cpp:98:20: required from here

source_file.cpp:82:34: error: ‘get_element’ was not declared in this scope, and no declarations were found by argument-dependent lookup at the point of instantiation [-fpermissive]

Entry e = (Entry)get_element(key);

source_file.cpp:82:34: note: declarations in dependent base ->‘HashSetBase’ are not found by unqualified lookup

source_file.cpp:82:34: note: use ‘this->get_element’ instead

Rukunujjaman Miaji
  • 1
  • 2

1 Answers1

0

finally i have sole the problem by modifying this line of code : this->get_element;

Rukunujjaman Miaji
  • 1
  • 2