7_6_even_odd.cpp

#include <iostream>
using namespace std;

template <class T>
class LinkedList{
    struct node{
        T x;
        node *next;
    };
    public:
    LinkedList(){
        head = NULL;
        curr = NULL;
    }
    node* getHead(){
        return head;
    }
    node* getCurrent(){
        return curr;
    }
    void addNode(struct node* b){
        b->next = head;
        head = b;
        if(curr == NULL)
            curr = head;
    }
    void addValue(T a){
        node *n = new node;
        n->x = a;
        n->next = head;
        head = n;
        if(curr == NULL)
            curr = head;
    }
    void rewind(){
        curr = head;
    }
    void next(){
        if( curr != NULL )
            curr = curr->next;
    }
    int getValue(){
        if( curr != NULL )
            return curr->x;
        return 0;
    }
    int hasValue(){
        return ( curr != NULL ? true : false );
    }
    void evenOddSort(){
        rewind();
        node *temp1, *temp2 = head->next;
        int i = 1;
        while(temp2->next!=NULL){
            int j = i, k = i-1;
            temp1 = temp2 = curr->next;
            while(j && curr->next->next){
                curr->next = curr->next->next;
                j--;
            }
            while(k && temp2->next)
                {
                temp2 = temp2->next;
                k--;
            }
            if(!j){
                if(curr->next->next)
                    temp2->next = curr->next->next;
                else
                    temp2->next = NULL;
                curr->next->next = temp1;
                next();
                i++;
            }
            else
                {
                curr->next = temp1;
                temp2->next = NULL;
            }
        }
        rewind();
    }

    private:
    node *head;
    node *curr;
};



int main(){
    LinkedList<int> L;
    L.addValue(12);
    L.addValue(11);
    L.addValue(10);
    L.addValue(9);
    L.addValue(8);
    L.addValue(7);
    L.addValue(6);
    L.addValue(5);
    L.addValue(4);
    L.addValue(3);
    L.addValue(2);
    L.addValue(1);
    L.addValue(0);
    L.rewind();
    while(L.hasValue())
        {
        cout << "BEFORE----Value: " << L.getValue();
        if(L.getValue()/10 < 1)
            cout << " ";
        cout << "  Pointer: " << L.getCurrent() << endl;
        L.next();
    }
    cout << "\n----------------------------------------------------\n" << endl;

    L.evenOddSort();
    while(L.hasValue())
        {
        cout << "AFTER-----Value: " << L.getValue();
        if(L.getValue()/10 < 1)
            cout << " ";
        cout << "  Pointer: " << L.getCurrent() << endl;
        L.next();
    }
    return 0;
}