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Merge Sort with display problem

newbieprog (6)
Can any pros/senpai in c++ notify me why I could not call the display function to show the random numbers and sorted array? I squeeze out my brain juice yet still I could not figure it out why. Really need helps badly

Assignment01.cpp
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 #include <iostream>
#include <cstdio>
#include <cstdlib>

using namespace std;

class mergenode{
public:
struct node

{
    int data;
    struct node* next;
};
typedef struct node* nodePtr;
        nodePtr curr;
        nodePtr temp;
        nodePtr head;
        nodePtr Node;
mergenode();
void addNode(int data);
bool Empty();
struct node* SortedMerge(node* a, node* b);
void display(struct node* counter);;
void MergeSort(struct node** Head);

private:

int calculateSize();
void Split(node* givennumber, node** Front, node** Back);
};

mergenode::mergenode(){
    curr= NULL;
    head=NULL;
    temp=NULL;
    Node=NULL;
    }

bool mergenode:: Empty() {
    return head == NULL;
}


void mergenode:: addNode(int data ){
    nodePtr n = new node;
    n->next = NULL;
    n->data = data;

    if(!Empty()){
        curr = head;

            while(curr->next !=NULL){
                curr = curr->next;

            }
        curr->next = n;
    }
    else{
        head = n;

    }
}

int mergenode:: calculateSize()
{
    int count = 0;
    Node= head;
    while(Node!=NULL){
        count++;
        Node = Node->next;
    }
    return count;

}


void mergenode::display(struct node* counter){

    while(counter != NULL)
    {
        cout<<counter->data<<" ";
        counter = counter-> next;
    }
 cout<<endl;
}



/* sorts the linked list by changing next pointers (not data) */

void mergenode::MergeSort(struct node** Head)
{
    node* head = *Head;
    node* a;
    node* b;
    if ((head == NULL) || (head->next == NULL))
    {
        return;
    }
    Split(head, &a, &b);
    MergeSort(&a);
    MergeSort(&b);
    *Head = SortedMerge(a, b);
}
/* merge the sorted linked lists */
struct mergenode:: node*mergenode:: SortedMerge(struct node* a, struct node* b)
{
    node* result = NULL;
    if (a == NULL)
        return b;
    else if (b==NULL)
        return a;
    if (a->data <= b->data)
    {
        result = a;
        result->next = SortedMerge(a->next, b);
        display(a);
    }
    else
    {
        result = b;
        result->next = SortedMerge(a, b->next);
        display(b);
    }
    return result;
}

/* Split the nodes of the given list into front and back halves*/
void mergenode::Split(node* givennumber, node** Front, node** Back)
{
    node* fast;
    node* slow;
    if (givennumber==NULL || givennumber->next==NULL)
    {
        *Front = givennumber;
        *Back = NULL;
    }
    else
    {
        slow = givennumber;
        fast = givennumber->next;
        while (fast != NULL)
        {
            fast = fast->next;
            if (fast != NULL)
            {
                slow = slow->next;
                fast = fast->next;
            }
        }
        *Front = givennumber;
        *Back = slow->next;
        slow->next = NULL;
        display(*Front);
        display(*Back);

    }
}



Last edited on
newbieprog (6)
versiongui.cpp
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#include <iostream>
#include <fstream>
#include <cstdlib>
#include <ctime>
#include "Assignment01.cpp"
using namespace std;

int main()
{
    mergenode mdata;
    selectionNode theData;
    srand(time(NULL));
    InsertionNode getdata;
    char choicesort;
    cout << "Select TypeOfSort" << endl;
    cout << "(a) Bubble Sort" << endl;
    cout << "(b) Selection Sort" << endl;
    cout << "(c) Insertion Sort" << endl;
    cout << "(d) Merge Sort" << endl;
    cin >> choicesort;
    cout << endl;

    switch(choicesort)
    {
    //bubble sort
    case 'a':
    case 'A':
    {
        char choicebubble;
        cout << "Select number::" << endl;
        cout << "(a) 20" << endl;
        cout << "(b) 200" << endl;
        cout << "(c) 2000" << endl;
        cout << "Choice: ";
        cin >> choicebubble;
        cout << endl;

            switch(choicebubble)
            {
            case 'a': //bubble sort20
            case 'A': //bubble sort20
            {
            bubbleNode node;
            bubbleNode();

            node.add20item();
            cout << "Random number :: ";
            node.display20();
            node.bubblesort20();
            cout << "Answer :: ";
            node.display20();
            system("pause");
            return 0;
            }
            break;

            case 'b': //bubble sort200
            case 'B': //bubble sort200
            {
            bubbleNode node;
            bubbleNode();

            node.add200item();
            cout << "Random number :: " ;
            node.display200();
            node.bubblesort200();
            cout << "\nAnswer :: ";
            node.display200();
            system("pause");
            return 0;
            }
            break;

            case 'c': //bubble sort2000
            case 'C': //bubble sort2000
            {
            bubbleNode node;
            bubbleNode();

            node.add2000item();
            cout << "Random number :: " ;
            node.display2000();
            node.bubblesort2000();
            cout << "\nAnswer :: ";
            node.display2000();
            system("pause");
            return 0;
            }
            break;

            default:
            cout << "Invalid choice";

            }
    } // end of bubble sort
    case 'b' :
    case 'B':
            {
                 char chNum;
            cout << "Select number::" << endl;
            cout << "(a) 20" << endl;
            cout << "(b) 200" << endl;
            cout << "(c) 2000" << endl;
            cout << "Choice: ";
            cin >> chNum;
            cout << endl;

            switch(chNum)
            {
            case 'a': //SS sort20
            case 'A': //SS sort20
            {
               for(int i=0 ; i<20 ; i++){
            int random= rand() % 99;
            theData.addNode(random);
                }
            cout << "Random number : " ;
            theData.display();
            theData.selectionSort();
            cout<<"Sorted : ";
            theData.display();
            system("pause");
            return 0;
            }
            break;

            case 'b': //SS 200
            case 'B': //SS 200
            {
             for(int i=0 ; i<200 ; i++){
            int random= rand() % 999;
            theData.addNode(random);
                }
            cout << "Random number : " ;
            theData.display();
            theData.selectionSortV2();
            cout<<"Sorted : ";
            theData.display();
            system("pause");
            return 0;
            }
            break;

            case 'c': //SS 2000
            case 'C': //SS 2000
            {
             for(int i=0 ; i<2000 ; i++){
            int random= rand() % 9999;
            theData.addNode(random);
                }
            cout << "Random number : " ;
            theData.display();
            theData.selectionSortV2();
            cout<<"Sorted : ";
            theData.display();
            system("pause");
            return 0;
            }
            break;


            }

    //ADD case B/C/D for another sort

            }// end of choice sort
    case 'c':
    case 'C':
    {
            char choiceinsertion;
            cout << "Select number::" << endl;
            cout << "(a) 20" << endl;
            cout << "(b) 200" << endl;
            cout << "(c) 2000" << endl;
            cout << "Choice: ";
            cin >> choiceinsertion;
            cout << endl;

            switch(choiceinsertion)
            {
            case 'a': //SS sort20
            case 'A': //SS sort20
            {
               for(int i=0 ; i<20 ; i++){
            int random= rand() % 99;
            getdata.addNode(random);
                }
            cout << "Random number : " ;
            getdata.display();
            getdata.InsertionSort();
            cout<<"Sorted : ";
            getdata.display();
            system("pause");
            return 0;
            }
            break;

            case 'b': //SS 200
            case 'B': //SS 200
            {
             for(int i=0 ; i<200 ; i++){
            int random= rand() % 999;
            getdata.addNode(random);
                }
            cout << "Random number : " ;
            getdata.display();
            getdata.InsertionSortX();
            cout<<"Sorted : ";
            getdata.display();
            system("pause");
            return 0;
            }
            break;

            case 'c': //SS 2000
            case 'C': //SS 2000
            {
             for(int i=0 ; i<2000 ; i++){
            int random= rand() % 9999;
            getdata.addNode(random);
                }
            cout << "Random number : " ;
            getdata.display();
            getdata.InsertionSortX();
            cout<<"Sorted : ";
            getdata.display();
            system("pause");
            return 0;
            }
            break;
            }

            }
case 'd':
case 'D':
    {
            char choicemerge;
            cout << "Select number::" << endl;
            cout << "(a) 20" << endl;
            cout << "(b) 200" << endl;
            cout << "(c) 2000" << endl;
            cout << "Choice: ";
            cin >> choicemerge;
            cout << endl;

            switch(choicemerge)
            {
            case 'a': //SS sort20
            case 'A': //SS sort20
            {
               for(int i=0 ; i<20 ; i++){
            int random= rand() % 99;
            mdata.addNode(random);
                }
            cout << "Random number : " ;
            mdata.display();
            mdata.MergeSort();
            cout<<"Sorted : ";
            mdata.display();
            system("pause");
            return 0;
            }
            break;

            case 'b': //SS 200
            case 'B': //SS 200
            {
             for(int i=0 ; i<200 ; i++){
            int random= rand() % 999;
            mdata.addNode(random);
                }
            cout << "Random number : " ;
            mdata.display();
            mdata.MergeSort();
            cout<<"Sorted : ";
            mdata.display();
            system("pause");
            return 0;
            }
            break;

            case 'c': //SS 2000
            case 'C': //SS 2000
            {
             for(int i=0 ; i<2000 ; i++){
            int random= rand() % 9999;
            mdata.addNode(random);
                }
            cout << "Random number : " ;
            mdata.display();
            mdata.MergeSort();
            cout<<"Sorted : ";
            mdata.display();
            system("pause");
            return 0;
            }
            break;
            }

            }
    }
}


Error at line 256, 257, 259, 273, 274, 276, 290, 291 and 293
P.S: ignore the selection, insertion and bubble sort.
Last edited on
ne555 (10692)
> Error at line 256, 257, 259, 273, 274, 276, 290, 291 and 293
¿what errors?

> ignore the selection, insertion and bubble sort.
remove them from your code snip.


> #include "Assignment01.cpp"
http://www.cplusplus.com/forum/general/140198/
http://www.cplusplus.com/forum/general/113904/
Last edited on
newbieprog (6)
> Error at line 256, 257, 259, 273, 274, 276, 290, 291 and 293
Unable to call the functions

> ignore the selection, insertion and bubble sort.
Cause this is the combination of my friends and my works, they did their selection, bubble and insertion sort. So it should be inside

> #include "Assignment01.cpp"
What's the problem of it?
ne555 (10692)
> Unable to call the functions
error: no matching function for call to ‘mergenode::display()’
||         mdata.display ();
||                        ^
note: candidate: void mergenode::display(mergenode::node*)
||  void mergenode::display (struct node* counter)
||       ^
note:   candidate expects 1 argument, 0 provided
the other are similar
For some reason you asked for a parameter, pass it then.


> Cause this is the combination of my friends and my works
¿so? their code is not related to your error, there is no need to include it.
When posting try to create a minimal example.


> What's the problem of it?
you are killing the purpose of the linker.
you may get the `multiple definition' error if your cpp is included several times.
newbieprog (6)
okay i changed it to another 

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#include <iostream>
#include <cstdio>
#include <cstdlib>
using namespace std;


struct node

{
    int data;
    struct node* next;
};
typedef struct node* nodePtr;
        nodePtr curr;
        nodePtr temp;
        nodePtr head;
        nodePtr Node;
        nodePtr counter;


void addNode(int data);
bool Empty();
struct node* SortedMerge(node* a, node* b);
void display_m(struct node* counter);
void MergeSort(struct node** Head);
void Split(node* givennumber, node** Front, node** Back);



bool Empty() {
    return head == NULL;
}


void addNode(int data ){
    nodePtr n = new node;
    n->next = NULL;
    n->data = data;

    if(!Empty()){
        curr = head;

            while(curr->next !=NULL){
                curr = curr->next;

            }
        curr->next = n;
    }
    else{
        head = n;

    }
}


void display(){
    counter = head;
    while(counter != NULL)
    {
        cout<<counter->data<<" ";
        counter = counter-> next;
    }
 cout<<endl;
}

void display_m(struct node* counter){

    while(counter != NULL)
    {
        cout<<counter->data<<" ";
        counter = counter-> next;
    }
 cout<<endl;
}





void MergeSort(struct node** Head)
{
    node* head = *Head;
    node* a;
    node* b;
    if ((head == NULL) || (head->next == NULL))
    {
        return;
    }
    Split(head, &a, &b);
    MergeSort(&a);
    MergeSort(&b);
    *Head = SortedMerge(a, b);
}

void MergeSort_2(struct node** Head)
{
    node* head = *Head;
    node* a;
    node* b;
    if ((head == NULL) || (head->next == NULL))
    {
        return;
    }
    Split(head, &a, &b);
    MergeSort_2(&a);
    MergeSort_2(&b);
    *Head = SortedMerge(a, b);
}


struct node* SortedMerge(struct node* a, struct node* b)
{
    node* result = NULL;
    if (a == NULL)
        return b;
    else if (b==NULL)
        return a;
    if (a->data <= b->data)
    {
        result = a;
        result->next = SortedMerge(a->next, b);
        display_m(a);
    }
    else
    {
        result = b;
        result->next = SortedMerge(a, b->next);
        display_m(b);
    }
    return result;
}




void Split(node* givennumber, node** Front, node** Back)
{
    node* fast;
    node* slow;
    if (givennumber==NULL || givennumber->next==NULL)
    {
        *Front = givennumber;
        *Back = NULL;
    }
    else
    {
        slow = givennumber;
        fast = givennumber->next;
        while (fast != NULL)
        {
            fast = fast->next;
            if (fast != NULL)
            {
                slow = slow->next;
                fast = fast->next;
            }
        }
        *Front = givennumber;
        *Back = slow->next;
        slow->next = NULL;
        display_m(*Front);
        display_m(*Back);

    }
}



int main()
{

    int i;
    char choice;
    cout << "Merge Sort Selection: " << endl;
    cout << "[1] 20 random numbers" << endl;
    cout << "[2] 200 random numbers" << endl;
    cout << "[3] 2000 random numbers" << endl;
    cin >> choice;
    cout << endl;

    switch(choice){
        case '1':
            {
            for(int i=0 ; i <20 ; i++){
            int random = rand() % 99 ;
            addNode(random);
            }
            cout << "20 Random Numbers: " ;
            display();
            cout<<"Sorting data: \n";
            MergeSort(&head);
            cout<< "\nResult: \n";
            display_m(head);
            system ("pause");
            return 0;
            }
            break;
        case '2':
            {
            for(int i=0 ; i <200 ; i++){
            int random = rand() % 99 ;
            addNode(random);
            }
            cout << "200 Random Numbers: " ;
            display();
            cout<<"Sorting data: \n";
            MergeSort(&head);
            cout<< "\nResult: \n";
            display_m(head);
            system ("pause");
            return 0;
            }
            break;
        case '3':
            {
            for(int i=0 ; i <2000 ; i++){
            int random = rand() % 99 ;
            addNode(random);
            }
            cout << "2000 Random Numbers: " ;
            display();
            cout<<"Sorting data: \n";
            MergeSort(&head);
            cout<< "\nResult: \n";
            display_m(head);
            system ("pause");
            return 0;
            }
            break;

    }

}


what if I wanted to list the result of Choice 2 and 3 without so much of steps that take years to show out the result?
Is there any problem in my void MergeSort?
Last edited on
ne555 (10692)
merge sort is O(n lg n) if the merge part can be done in O(n)
The `display_m()' in your `SortedMerge()' are making it O(n^2), as you are printing a whole list after resolving one conflict.

I don't understand why you print you much, just don't.


Also, your code is hideous. You may use a `list' class, and avoid all those globals.

Your `addNode()' is O(n) when it could easily be O(1)
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