有人可以告诉我为什么从我的链表中打印垃圾

  • 本文关键字:链表 打印 c++ linked-list
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所以我正在为学校做这个项目。我有一切工作。我首先构造了链表,在代码中你可以看到它把所有东西都打印出来。当我尝试使用菜单将项目插入列表时,它似乎有效。我已经放了几张打印件,看看发生了什么。当我打印列表时,只有菜单估算的项目损坏了。

我已经查看了几个表明相同问题的帖子,但我没有看到问题可能在我的代码中的位置。

你们能不能看看函数,看看我是否做错了什么。据我所知,这一切似乎都有效,但输出却充满了垃圾。感谢您的帮助这是该项目的代码

字.h

class Word
{
public:
    void SetEnglish(char *word);
    char *GetEnglish();
    void SetFinnish(char *word);
    char *GetFinnish();
    void SetPrev(Word *word);
    Word *GetPrev();
    void SetNext(Word *word);
    Word *GetNext();
private:
    char *English;
    char *Finnish;
    Word *prev;          //pointer to previous node 
    Word *next;          //pointer to next node 

};
class dlist
{
public:
    Word *front;       //pointer to front of list   
    Word *back;        //pointer to back of list  
dlist()
{
    front=NULL;
    back=NULL;
}
void insertFront(char *Eng, char *Fin);             
int insertBack(char *Eng, char *Fin);
void insertBefore(char *Eng, char *Fin, Word *nodeB);
void insertAfter(char *Eng, char *Fin, Word *nodeA);
void printDListFront();
};

字.cpp

#include <iostream>
#include "Word.h"
#define Word_OK (0)
using namespace std;
//sets the English word
void Word::SetEnglish(char *Eng)
{
    English = Eng;
}
//gets the English word
char *Word::GetEnglish()
{
    return English;
}
//sets the Finnish word
void Word::SetFinnish(char *Fin)
{
    Finnish = Fin;
}
//gets the Finnish word
char *Word::GetFinnish()
{
    return Finnish;
}
//sets the previous node
void Word::SetPrev(Word *node)
{
    prev = node;
}
//gets the previous node
Word *Word::GetPrev()
{
    return prev;
}
//sets the next node
void Word::SetNext(Word *node)
{
    next = node;
}
//gets the next node
Word *Word::GetNext()
{
    return next;
}
//insert a node after the last node 
int dlist::insertBack (char *Eng, char *Fin)
{          
    cout << "English: " << Eng << " " << "Finnish :" << Fin << "n";
    if(this->back==NULL)
    {
        cout<<"insert at back";
        insertFront(Eng, Fin);
    }
    else
    {
        cout<<"insert at back";
        insertAfter(Eng, Fin, this->back  );
    }
    return Word_OK;
}
//insert a node before the front node 
void dlist::insertFront (char *Eng, char *Fin)
    {
    Word *newNode;
    if(this->front==NULL)
    {
        newNode=new Word();
        this->front=newNode;
        this->back =newNode;
        newNode->SetPrev(NULL);
        newNode->SetNext(NULL);
        newNode->SetEnglish(Eng);
        newNode->SetFinnish(Fin);
    }
    else
    {
        insertBefore(Eng, Fin, this->front );
    }
}
//insert a node after  nodeB
void dlist::insertAfter(char *Eng, char *Fin, Word *nodeB)
{
    cout << "nEnglish1: " << Eng << " " << "Finnish1: " << Fin << "n";
    Word *newNode;
    newNode=new Word();
    newNode->SetNext(nodeB->GetNext()) ;
    newNode->SetPrev(nodeB);
    newNode->SetEnglish(Eng);
    newNode->SetFinnish(Fin);
    if(nodeB->GetNext()==NULL)
    {
        cout<<"n "<< endl;
        this->back =newNode; 
    }
    nodeB->SetNext(newNode);
    cout<<"2"<<endl;
}
//insert a node before nodeB
void dlist::insertBefore(char *Eng, char *Fin, Word *nodeB)    
{
    Word *newNode;
    newNode=new Word();
    newNode->SetPrev(nodeB->GetPrev());
    newNode->SetNext(nodeB);
    newNode->SetEnglish(Eng); 
    newNode->SetFinnish(Fin); 
    if(nodeB->GetPrev()==NULL)
    {
        this->front=newNode; 
    }
    nodeB->SetPrev(newNode);
}

//Print the list from front 
void dlist::printDListFront()
{
    Word* curr2;
    curr2= this->front;
    cout<<"n------------------------n";
    cout<<"Words in the Dictionary: n";
    cout<<"------------------------n";
    while(curr2!=NULL)
    {
        cout<<curr2->GetEnglish();
        cout<<" "<< curr2->GetFinnish()<<"n";
        curr2=curr2->GetNext();
    }
    cout<<endl;
}// print the Double Linked List from front

主.cpp

#include <iostream>
#include <fstream>
#include <cstdlib>
#include <string.h>
#include "menu.h"
#include "Word.h"
using namespace std;
#define Word_OK (0)
#define Word_Not_Found (-1)
#define Word_already_Exist (-2)
#define Word_too_big (-3)
#define Dictionary_empty (-4)
#define File_error (-5)
#define Memory_error (-6)
#define Word_Unknown_Error (-20)
#define Buffer (200)
#define Max_len (30)
#define FILE_NAME "dictionary.txt"
/* Search the word in the list and print it if found. 
   return an error code if not found or the dictionary is empty. */
int SearchWord();
/* Add a word in the list from user input.
   return an error code if the word already exist or if input is too long. */
int InsertWord(dlist *w);
/* Function used by InsertWord() and InitDictionary() to insert a new word in 
   the list at right position (order alphabetically by english word).
   return an error code if there is a memory allocation problem. */
int chainWord(char *en, char *fi, Word *w);
/* Remove a word from the list.
   return an error code if word not found. */
int DeleteWord();
/* Show all the words in the dictionary. This was first a debug function; but
   since it works, I kept it. Considere that as an extra feature.
   return an error code if the dictionnary is empty. */
int ShowAllWord(dlist *list);
/* Print error if something goes wrong. */
void PrintError(int aErrorCode);
/* Read the saved words from the file and load it to the dictionary.
   return an error code if it don't manage to open the file. */
int InitDictionary(dlist *list);
/* Save the words in the file and clean the memory before leaving the program.
   return an error code if there is a problem with the file. */
int ExitDictionary();
int putDictionary(Word *w);
void putword(dlist *st)
{
    char eng[30], fin[30];
    cout << "English word: " ;
    cin >> eng;
    cout << "Finnish word: ";
    cin >> fin;
    st->insertBack(eng, fin);
}
void main()
{
    char eng[30], fin[30];
    dlist *st ;
    st= new dlist();
    cout << "English word: " ;
    cin >> eng;
    cout << "Finnish word: ";
    cin >> fin;
    st->insertBack(eng, fin); 
    st->insertBack("hello", "hei"); 
    st->insertBack("we", "me"); 
    st->insertBack("they", "he"); 
    st->insertBack("truck", "rekka") ;
    st->printDListFront ();
    Menu m;
    m.PrintHeader();
    m.PrintMenu();
    //PrintError(InitDictionary(st));
    int errorcode = 0;
    char c;
    cout << "Choose option: ";
    cin >> c;
    fflush(stdin); //I want one option at the time, so flush the end of line
    while(c != 'e' && c != 'E'){
        switch(c){
            case 's':
            case 'S':
               //  errorcode = SearchWord();
                 break;
            case 'i':
            case 'I':
                  putword(st);
                 break;
            case 'd':
            case 'D':
               //  errorcode = DeleteWord();
                 break;
            case 'a':
            case 'A':
               errorcode = ShowAllWord(st);
                 break;
            default:
                 system("cls");
                 m.PrintMenu();
        }
        PrintError(errorcode);
        cout << "Choose option: ";
        cin >> c;
        fflush(stdin);
    }
    //PrintError(ExitDictionary());

    system("pause");
}

int InsertWord(dlist *list)
{
    char eng[30], fin[30];
    cout << "English word: " ;
    cin >> eng;
    cout << "Finnish word: ";
    cin >> fin;
    int res = list->insertBack(eng, fin);
    return res;
}
int ShowAllWord(dlist *list)
{
    list->printDListFront ();
    return 0;
}
void PrintError(int aErrorCode){
     switch(aErrorCode){
         case Word_OK:
            break;
         case Word_Not_Found:
            cout << "Word not found!" << endl;
            break;
         case Word_already_Exist:
            cout << "The word already exist!" << endl;
            break;
         case Word_too_big:
            cout << "The word is too big!" << endl;
            break;
         case Dictionary_empty:
            cout << "Dictionary is empty!" << endl;
            break;
         case File_error:
            cout << "Error with file!" << endl;
            break;
         case Memory_error:
            cout << "Memory allocation problem!" << endl;
            break;
         case Word_Unknown_Error:
         default:
            cout << "Oppps Unknown Error!" << endl;
            break;
     }                       
} 

菜单.h

#ifndef _MENU_H_
#define _MENU_H_
//this class was created as an exercise and also to reduce the size of code of
//the main.
class Menu{
    public:
       /*print the information about the program and the author.*/
       void PrintHeader();
       /*print the options for the user.*/
       void PrintMenu();
};
#endif    

菜单.cpp

#include <iostream>
#include "menu.h"
using namespace std;
/* Implementation of the menu class. */
void Menu::PrintHeader(){
     cout << "*************************************" << endl
          << "****      Dictionary             ****" << endl
          << "****      By Your Name and ID    ****" << endl;
}
void Menu::PrintMenu(){
     cout << "*************************************" << endl
          << "***             MENU              ***" << endl
          << "*************************************" << endl
          << "S - Search"         << endl
          << "I - Insert"         << endl
          << "D - Delete"         << endl
          << "A - Show all words" << endl
          << "E - Exit"           << endl
          << "  - Any other key to clear the screen" << endl
          << "*************************************" << endl;
} 
char eng[30], fin[30];
cout << "English word: " ;
cin >> eng;
cout << "Finnish word: ";
cin >> fin;
int res = list->insertBack(eng, fin);

您将本地数组用于 insertBack 参数,并且 Word 类还保存指向它们的指针。一旦函数终止,它们将超出范围,之后的值可以是任何值。您应该存储在 Word 类中的是字符串的副本,位于其自己的存储中(动态或静态(。

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