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Copy pathdoublelist.cpp
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148 lines (125 loc) · 2.68 KB
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#include "doublelist.h"
void createList(List &L) {
first(L) = NULL;
last(L) = NULL;
}
address allocate(infotype x) {
address P;
P = new elmlist;
info(P) = x;
next(P) = NULL;
prev(P) = NULL;
return P;
}
void deallocate(address &P) {
delete P;
P = NULL;
}
void printInfo(List L) {
if(first(L)!=NULL &&last(L)!=NULL) {
address P = first(L);
while(P!=last(L)) {
cout<<info(P)<<", ";
P = next(P);
}
cout<<info(P)<<", ";
}
cout<<endl;
}
void insertLast(List &L, address P) {
if(first(L)!=NULL && last(L)!=NULL) {
prev(P) = last(L);
next(last(L)) = P;
last(L) = P;
} else {
first(L) = P;
last(L) = P;
}
}
void deleteFirst(List &L, address &P) {
if(first(L)==last(L)){
P = first(L);
first(L)=NULL;
last(L)=NULL;
}
else if(next(first(L))==last(L)){
P= last(L);
last(L)=first(L);
next(first(L))=NULL;
prev(P)=NULL;
}else{
P = first(L);
first(L) = next(P);
next(P)= NULL;
prev(first(L)) = NULL;
}
}
void insertFirst(List &L, address P) {
if(first(L)!=NULL && last(L)!=NULL) {
next(P) = first(L);
prev(first(L)) = P;
first(L) = P;
} else {
first(L) = P;
last(L) = P;
}
}
address findElement(List L, infotype x) {
address P = first(L);
while ((info(P) != x)&&(next(P) != NULL)){
P = next(P);
}
if (info(P)== x){
return P;
}else{
return NULL;
}
}
void insertAfter(List &L, address Prec, address P) {
if(Prec != NULL){
if(next(Prec)==NULL){
insertLast(L,P);
}
else{
next(P) = next(Prec);
prev(next(Prec))= P;
next(Prec)=P;
prev(P)=Prec;
}
}
}
void deleteLast(List &L, address &P) {
if(first(L)==last(L)){
P = first(L);
first(L)=NULL;
last(L)=NULL;
}
else if(next(first(L))==last(L)){
P= last(L);
last(L)=first(L);
next(first(L))=NULL;
prev(P)=NULL;
}
else if(last(L) != NULL){
P = last(L);
last(L) = prev(P);
next(prev(P))=NULL;
prev(P)=NULL;
}
}
void deleteAfter(List &L, address Prec, address &P) {
if(Prec != NULL){
if(next(Prec)!=NULL){
if(next(Prec)==last(L)){
deleteLast(L,P);
}
else{
P = next(Prec);
next(Prec)=next(P);
prev(next(P)) = Prec;
next(P) = NULL;
prev(P) = NULL;
}
}
}
}