c++ - 构建运行正常，但运行时崩溃？

Question

我仍在学习有关ADT的信息，我从自己那里获得了许多链接列出的代码，但是我的代码崩溃了，有人可以告诉我我错在哪里吗？
我的程序是输入笔记本电脑品牌，然后输入品牌的类型。

#ifndef SISWA_H_INCLUDED
#define SISWA_H_INCLUDED

struct ALaptop{
    char tipe[255];
};

struct ILaptop {
    char merek[255];
    ALaptop anak;
};

struct TNode {
    ILaptop induk;
    TNode *next;
    TNode *prev;
    TNode *up;
    TNode *down;
};

struct List {
    TNode *head;
    TNode *tail;
};

void insert_induk(List *&list_,TNode *&Ilaptop);
void delete_induk(List *list_,char cari[]);
void insert_anak(TNode *&C,TNode *Ilaptop);
void insert_anak2(List *list_,char cari[]);
TNode* create_induk(char merek[]);
TNode* create_anak(char tipe[]);
void view(List *list_);
int Empty(List *list_);
void createList(List *list_);

#endif // SISWA_H_INCLUDED



#include "siswa.h"
#include <string.h>
#include <iostream>

using namespace std;

void insert_induk(List *&list_,TNode *&Ilaptop){
    char p;
    char tipe[255];
    if (Empty(list_)==1){
        Ilaptop=list_->head;
        Ilaptop=list_->tail;
    }
    else{
        list_->head->prev=Ilaptop;
        Ilaptop->next=list_->head;
        list_->head=Ilaptop;
    }
    TNode *bantu=Ilaptop;
    cout<<"masukkan tipe laptop? (y/n) : ";
    cin>>p;
    while(p=='y'||p=='Y'){
        cout<<"masukkan tipe laptop : ";
        cin.ignore();
        cin.getline(tipe,sizeof tipe);
        insert_anak(bantu,create_anak(tipe));
        cout<<"masukkan tipe laptop lagi? (y/n) : ";
        cin>>p;
    }
}

void insert_anak(TNode *&C,TNode *Ilaptop){
    C->down=Ilaptop;
    Ilaptop->up=C;
    C=Ilaptop;
}

void insert_anak2(List *list_,char cari[]){
    TNode *bantu;
    char tipe[255];
    char p;
    bantu=list_->head;
    if (Empty(list_)==0){
        while (bantu!=NULL){
            if(strcmp(bantu->induk.merek,cari)==0){
                TNode *bantu10=bantu;
                cout<<"Merek Laptop "<<bantu->induk.merek<<endl<<endl;
                cout<<"masukkan tipe laptop : ";
                cin.ignore();
                cin.getline(tipe,sizeof tipe);
                insert_anak(bantu10,create_anak(tipe));
                cout<<"masukkan tipe laptop lagi? (y/n) : ";
                cin>>p;
                while(p=='y'||p=='Y'){
                    cout<<"masukkan tipe laptop : ";
                    cin.ignore();
                    cin.getline(tipe,sizeof tipe);
                    insert_anak(bantu10,create_anak(tipe));
                    cout<<"masukkan tipe laptop lagi? (y/n) : ";
                    cin>>p;
                }
            }
            else {
                bantu=bantu->next;
            }
        }
        cout<<"Data tidak ada!";
    }
    else{
        cout<<"Data masih kosong";
    }
}

void delete_induk(List *list_,char cari[]){
    TNode *bantu,*bantu2,*bantu3;
    bantu=list_->head;
    if (Empty(list_)==0){
        while (bantu!=NULL){
            if(strcmp(bantu->induk.merek,cari)==0){
                bantu3=bantu;
                bantu3->prev->next=bantu->next;
                bantu->next->prev=bantu3;
                while (bantu!=NULL) {
                    bantu2=bantu;
                    bantu=bantu->down;
                    delete bantu2;
                }
                return;
            }
            else {
                bantu=bantu->next;
            }
        }
        cout<<"Data tidak ada!";
    }
    else{
        cout<<"Data masih kosong";
    }
}


TNode* create_induk(char merek[]){
    TNode *baru=new TNode;
    baru->next=NULL;
    baru->prev=NULL;
    baru->up=NULL;
    baru->down=NULL;
    strcpy(baru->induk.merek,merek);
    return baru;
}

TNode* create_anak(char tipe[]){
    TNode *baru=new TNode;
    baru->next=NULL;
    baru->prev=NULL;
    baru->up=NULL;
    baru->down=NULL;
    strcpy(baru->induk.anak.tipe,tipe);
    return baru;
}

void view(List *list_){
    TNode *bantu2;
    TNode *bantu=list_->head;
    if (Empty(list_)==0){
        while(bantu!=NULL){
            cout<<"| ";
            bantu2=bantu->down;
            while(bantu2!=NULL){
                cout<<bantu2->induk.anak.tipe<<" | ";
                bantu2=bantu->down;
            }
            bantu=bantu->next;
        }
    }
    else{
        cout<<"Data masih kosong";
    }
}

int Empty(List *list_){
    if (list_->head==NULL){
        return 1;
    }
    else {
        return 0;
    }
}

void createList(List *list_){
    list_->head=NULL;
    list_->tail=NULL;
}



#include <iostream>
#include <stdlib.h>
#include <conio.h>
#include "siswa.h"

using namespace std;



int main()
{
List *B;
int pil;
char merk[255];
TNode *induk;
createList(B);
menu:
cout<<"1. Tambah Merek Laptop\n2. Tambah Tipe Laptop\n3. Hapus Merek Laptop beserta tipe nya\n4. View seluruh Laptop\nMasukkan pilihan : ";
cin>>pil;

    switch (pil){
        case 1: cout<<"Masukkan Merek Laptop : ";
                cin.ignore();
                cin.getline(merk,sizeof merk);
                induk=create_induk(merk);
                insert_induk(B,induk);
                getch();
                goto menu;
        case 2: cout<<"Masukkan Merek Laptop yang ingin ditambahkan Tipe nya : ";
                cin.ignore();
                cin.getline(merk,sizeof merk);
                insert_anak2(B,merk);
                getch();
                goto menu;
        case 3: cout<<"Masukkan Merek Laptop yang ingin dihapus : ";
                cin.ignore();
                cin.getline(merk,sizeof merk);
                delete_induk(B,merk);
                getch();
                goto menu;
        case 4: view(B);
                getch();
                goto menu;
        default:getch();
                goto menu;
    }
    return 0;
}

我真的不知道问题出在哪里，算法错误？

Answer 1

问题是在这条线

List* B;

将此行更改为以下行；

List* B = new List();

希望这可以帮助。