C++单链表的文件存取

素颜马尾好姑娘i 2022-11-04 12:26 168阅读 0赞

#include <stdlib.h>
    #include <iostream>
    #include <fstream>
    using namespace std;
    #define ElemType int
    
    //C++单链表结点类
    class LNode { 
    public:
    	ElemType data;
    	LNode* next;
    };
    
    //C++单链表类
    class LinkList { 
    private:
    	LNode *head;
    public:
    	LinkList();
    	void createList();
    	void displayList();
    	LNode* getHead();
    };
    
    void menu(LinkList* list);
    void save(LinkList* list);
    void read(LinkList* list);
    
    int main() { 
    
    	LinkList list;
    	menu(&list);
    }
    
    //构造方法
    LinkList::LinkList() { 
    	head = new LNode();
    	head -> next = NULL;
    }
    
    //创建单链表
    void LinkList::createList() { 
    	LNode* tail = head;
    	ElemType x;
    	cout << "尾插法，请输入整数，输入999截止" << endl;
    	while (cin >> x) { 
    		if (x == 999) { 
    			return;
    		}
    		LNode* p = new LNode;
    		p->data = x;
    		p->next = NULL;
    		tail->next = p;
    		tail = p;
    	}
    }
    
    
    //打印单链表
    void LinkList::displayList() { 
    	LNode* p = head->next;
    	while (p) { 
    		cout << p->data << " ";
    		p = p->next;
    	}
    	cout << endl;
    }
    
    //获取单链表头结点地址
    LNode * LinkList::getHead() { 
    	return head;
    }
    
    //菜单
    void menu(LinkList* list) { 
    	int a;
    	cout << "************************************" << endl;
    	cout << "** C++链表的文件存取问题 **" << endl;
    	cout << "************************************" << endl;
    	while (1) { 
    		system("pause");
    		system("cls");
    		cout << "********************************" << endl;
    		cout << "* 1.创建单链表。 *" << endl;
    		cout << "* 2.打印单链表。 *" << endl;
    		cout << "* 3.保存单链表。 *" << endl;
    		cout << "* 4.读取单链表。 *" << endl;
    		cout << "* 5.按其它键退出并保存。*" << endl;
    		cout << "********************************" << endl;
    		cin >> a;
    		switch (a) { 
    		case 1:
    			list->createList();
    			break;
    
    		case 2:
    			list->displayList();
    			break;
    		case 3:
    			save(list);
    			break;
    
    		case 4:
    			read(list);
    			break;
    
    		default:
    			save(list);
    			return;
    		}
    	}
    }
    //保存单链表
    void save(LinkList* list) { 
    	LNode* p = list->getHead()->next;
    	ofstream outfile;
    	outfile.open("list.txt", ios::binary);
    	if (!outfile) { 
    		cerr << "open failed" << endl;
    		return;
    	}
    	while (p) { 
    		//cout << p->data << endl;
    		outfile.write((char*)p, sizeof(LNode));
    		p = p->next;
    	}
    	outfile.close();
    	cout << "链表已保存到 list.txt" << endl;
    }
    
    //读取单链表
    void read(LinkList* list) { 
    	LNode* p = list->getHead();
    	ifstream infile;
    	infile.open("list.txt", ios::binary);
    	if (!infile) { 
    		cout << "打开文件失败" << endl;
    	}
    	/* * infile.eof()、iFlie.peek()会多读一行 */
    	while (infile.peek() != EOF) { 
    		LNode* q = new LNode;
    		infile.read((char*)q, sizeof(LNode));
    		cout << q->data << endl;
    		q->next = NULL;
    		p->next = q;
    		p = q;
    	}
    	cout << "链表读取成功" << endl;
    }