list.cpp

#include "list.h"
#include "my_data.h"

void createList(List &L) {
    /**
    * FS : set first(L) and last(L) with Null
    */
    //-------------your code here-------------
    first(L) = NULL;
    last(L) = NULL;


    //----------------------------------------
}

address allocate(infotype x) {
    /**
    * FS : return new list element with info = x and next element is Null
    */

    address P;
    //-------------your code here-------------
    P = new elmlist;
    info(P).ID = x.ID;
    info(P).name = x.name;
    info(P).rank = x.rank;
    info(P).score = x.score;

    next(P) = NULL;
    prev(P) = NULL;
    //----------------------------------------
    return P;
}

void deallocate(address &P) {
    /**
    * FS : delete element pointed by P
    */
    //-------------your code here-------------
    delete P;
    //----------------------------------------
}

void insertFirst(List &L, address P) {
    /**
    * IS : List L may be empty
    * FS : element pointed by P became the first element in List L
    */
    //-------------your code here-------------
    if (first(L)!= NULL){
        next(P) = first(L);
        prev(first(L)) = P;
        first(L) = P;
    } else {
        first(L) = P;
        last(L) = P;
    }
    //----------------------------------------
}

void insertLast(List &L, address P) {
    /**
    * IS : List L may be empty
    * FS : element pointed by P became the last element in List L
    */
    //-------------your code here-------------
    next(last(L)) = P;
    prev(P) = last(L);
    last(L) = P;
    //----------------------------------------
}

address findElm(List L, infotype x) {
    /**
    * IS : List L may be empty
    * FS : returns element with info.ID = x.ID,
           return Null if such ID is not found
    */

    address P;
    //-------------your code here-------------
    P = first(L);

    while (P != NULL && info(P).ID != x.ID){
        P = next(P);
    }
    //----------------------------------------
    return P;
}

void deleteFirst(List &L, address &P) {
    /**
    * IS : List L may be empty
    * FS : first element in List L is removed and is pointed by P
    */
    //-------------your code here-------------
    if (first(L) == last(L)){
        P = first(L);
        first(L) = NULL;
        last(L) = NULL;
    } else if (first(L) != NULL ) {
        P = first(L);
        first(L) = next(P);
        next(P) = NULL;
        prev(first(L)) = NULL;
    }
    //----------------------------------------
}

void deleteLast(List &L, address &P) {
    /**
    * IS : List L may be empty
    * FS : last element in List L is removed and is pointed by P
    */
    //-------------your code here-------------
    if (last(L) != NULL){
        P = last(L);
        last(L) = prev(P);
        prev(P) = NULL;
        next(last(L)) = NULL;
    }else if (first(L) == last(L)){
        P = first(L);
        first(L) = NULL;
        last(L) = NULL;
    }
    //----------------------------------------
}

void printInfo(List L) {
    /**
    * FS : view info of all element inside List L,
    *      call the view_data function from my_data.h to print the info
    */
    //-------------your code here-------------
    address P = first(L);

    while (P != NULL ){
        view_data(info(P));
        P = next(P);
    }
    cout<<endl;
    //----------------------------------------
}


void insertAfter(List &L, address Prec, address P) {
    /**
    * IS : Prec and P is not NULL
    * FS : element pointed by P is placed behind the element
    *      pointed by pointer Prec
    */
    //-------------your code here-------------
    if (first(L) == NULL){
        insertFirst(L,P);
    }else if (first(L) !=  last(L) && Prec != NULL){
        next(P) = next(Prec);
        prev(P) = Prec;
        prev(next(Prec)) = P;
        next(Prec) = P;
    }else if (Prec != NULL){
        insertLast(L,P);
    }
    //----------------------------------------

}
void deleteAfter(List &L, address Prec, address &P) {
    /**
    * IS : Prec is not NULL
    * FS : element which was before behind an element pointed by Prec
    *      is removed and pointed by pointer P
    */
    //-------------your code here-------------
    if (first(L) == last(L) && Prec != NULL){
        deleteFirst(L,P);
    } else if (next(Prec) != last(L) && Prec != NULL){
        P = next(Prec);
        next(Prec) = next(P);
        prev(next(P)) = Prec;
        next(P) = NULL;
        prev(P) = NULL;
    } else if (Prec != NULL){
        deleteLast(L,P);
    }

    //----------------------------------------
}