ddsssa

#include <iostream>
using namespace std;
struct Node {
    int info;
    Node* next;
};
typedef Node* PNode;
typedef Node* LinkedList;

void initializeList(LinkedList& list) {
    list = NULL;
    }

bool IsEmpty (LinkedList list){
    return(list == NULL);
}

void InsertBegin(LinkedList &list, int K){
    PNode Q = new Node;
    Q-> info = K;
    if(list == NULL){
        Q->next = NULL;
        list = Q;
    }
    else{
        Q->next = list;
        list = Q;
    }
}

PNode SearchNode(LinkedList& list, int K){
    PNode P = list;
    while(P != 0){
        if(P->info==K)
            return P;
    }
    return 0;
}

PNode InsertAfter(LinkedList& list, PNode P, int K){
    PNode Q = new Node;
    Q->info = K;
    if(list == NULL){
        Q->next = NULL;
        list = Q;
    }
    else {
        if (P==NULL) return NULL;
        Q->next = P->next;
        P->next = Q;    
     }
     return Q;
}

PNode InsertBefore(LinkedList& list, PNode P, int K){
    PNode Q = new Node;
    Q->info = K;
    if(list==NULL){
        list = Q;
        Q->next = NULL;
        return Q;
    }
    else {
        if(P==NULL) return NULL;
        Q->info = P->info;
        P->info=K;
        Q->next = P->next;
        P->next = Q;
    }
    return P;
}

void DeleteNode (LinkedList& list, PNode P){
    if (list == NULL) cout << "NULL"<<endl;
    else {
        P = list;
        list = list->next;
        delete P;
    }
}

void DeleteValue(LinkedList& list, int K) {
    PNode P = list;
    PNode prev = NULL;

    while (P != NULL && P->info == K) {
        // Delete the node at the beginning
        list = P->next;
        delete P;
        P = list;
    }

    while (P != NULL) {
        while (P != NULL && P->info != K) {
            prev = P;
            P = P->next;
        }

        if (P == NULL) {
            return; // Element not found
        }

        // Unlink the node with value K
        prev->next = P->next;
        delete P;
        P = prev->next;
    }
}


float average(LinkedList list){
    float avg = 0;
    int count = 0;
    PNode P = list;
    while(P != NULL){
        avg += P->info;
        P = P->next;
        count++;
    }
    return avg/count;
}

void display(LinkedList list){
    PNode P = list;
    while(P != NULL){
        cout << P->info << " ";
        P = P->next;
    }
    cout <<endl;
}

int main(){
    LinkedList N;
    initializeList (N);
    InsertBegin (N, 23);
    InsertBegin (N,24);
    InsertBegin (N,25);
    InsertBegin (N,24);
    InsertBegin (N,26);
    InsertBegin (N,29);
    InsertBegin (N,69);
    InsertBegin (N,24);
    display(N);

    cout << average(N) <<endl;

    // Delete nodes with value 24
    int valueToDelete = 24;
    DeleteValue(N, valueToDelete);
    cout << "After deleting nodes with value " << valueToDelete << ": ";
    display(N);


    //PNode nodeToDelete = SearchNode(N, 23);
    DeleteNode(N, SearchNode(N,23));
    display (N);

    cout << average(N) <<endl;

    int valueToInsertBefore = 24;
    PNode nodeToInsertBefore = SearchNode(N, 29);
    int newValueBefore = 25;
    InsertBefore(N, nodeToInsertBefore, newValueBefore);
    cout << "After inserting " << newValueBefore << " before " << "29" << ": ";
    display(N);
    
    int valueToInsertAfter = 24;
    //PNode nodeToInsertAfter = SearchNode(N, valueToInsertAfter);

    int newValueAfter = 49;
    //InsertAfter(N, nodeToInsertAfter, newValueAfter);

    cout << "After inserting " << newValueAfter << " after " << valueToInsertAfter << ": ";
    display(N);
}