具有多个数据项的链接列表 [英] Linked List with Multiple Data Items

问题描述

我正在尝试创建一个链接列表，其中不仅包含一个数据。该程序将运行并允许我输入尽可能多的结构，但是当我退出它时，它将正确打印输入的最后一个结构，两次，然后崩溃。



我假设我正在做一些不正确的指针。



这里是代码：

I''m trying to create a linked list which contains more than just a single piece of data. The program will run and allow me to enter as many structs as I want but when I quit it, it will correctly print out the last structure entered, twice, and then crash.

I assume I''m doing something not right with the pointers.

Here''s the code:

void main(void)
{
	int x;
	struct Student
	{
		int id;
		string name;
		string courseCode;
		struct Student *next; 
	} *start, *p;

	Student student;
	start = NULL; 
	
	printf("Enter a sequence of integers, letter to end: ");
	while(cin>>x)
	{
		p = &student;
		start = (Student *)malloc(sizeof(struct Student));
		if(start == NULL)
		{
			cout<<"Not enough memory";
			exit(1);
		}
		cout<<"Enter Student ID: ";
		cin>>student.id;
		cin.sync();
		cout<<endl<<"Enter Student Name: ";
		getline(cin, student.name);
		cin.sync();
		cout<<endl<<"Enter Course Code: ";
		getline(cin, student.courseCode);
		cin.sync();
		
		student.next = p;

	}

	cout<<endl<<"In reverse order, the following details were entered: "<<endl;
	

	for(p = start; p != NULL; p = p->next)
	{
		cout<<student.id<<endl;
		cout<<student.name<<endl;
		cout<<student.courseCode<<endl;
	}
}

推荐答案

在最后一个循环中，你打印<$ c $的数据c>学生而不是 p 。

学生在循环中没有变化，它的变化是 p 所以你应该打印它。



另外，在C ++中，当你有 new 时，你真的不想打电话给 malloc ，这些链接会指出你正确的方向;



http://msdn.microsoft.com/en-us/library/kewsb8ba(v = vs.71）.aspx [ ^ ]

http://stackoverflow.com/questions/655065/when-should-i- use-the-new-keyword-in-c [ ^ ]





这个稍微改变的实现类型 - 我想你想做什么;

In the last loop you''re printing the data for student instead of for p.
student doesn''t change in the loop, it''s p that changes so you should be printing that instead.

Also, in C++ you really don''t want to call malloc when you have new, these links will point you in the right direction;

http://msdn.microsoft.com/en-us/library/kewsb8ba(v=vs.71).aspx[^]
http://stackoverflow.com/questions/655065/when-should-i-use-the-new-keyword-in-c[^]


This slightly changed implementation kind-of does what you want I think;

#include<iostream>
#include<string>

using namespace std;

struct Student
{
    int id;
    string name;
    string courseCode;
    struct Student* next;
};


void main(void)
{
    int x;

    Student* previous = NULL;
    Student* start = NULL;

    printf("Enter a sequence of integers, letter to end: ");
    while(cin>>x)
    {
        Student* student = new Student;
        student->next = NULL;

        if (start == NULL)
            start = student;

        cout<<"Enter Student ID: ";
        cin>>student->id;
        cin.sync();
        cout<<endl<<"Enter Student Name: ";
        getline(cin, student->name);
        cin.sync();
        cout<<endl<<"Enter Course Code: ";
        getline(cin, student->courseCode);
        cin.sync();

        if (previous != NULL)
            previous->next = student;

        previous = student;
    }

    cout<<endl<<"In reverse order, the following details were entered: "<<endl;


    for(Student* p = start; p != NULL; p = p->next)
    {
        cout<<p->id<<endl;
        cout<<p->name<<endl;
        cout<<p->courseCode<<endl;
    }
}

希望这会有所帮助，

Fredrik

Hope this helps,
Fredrik

这篇关于具有多个数据项的链接列表的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！