Question

该程序是一个链接列表程序，所有运行在我必须对该程序进行一些重大更改之前。调试程序时，一切顺利，直到出现此错误的代码的最后一行：

| 175 |错误：在输入末尾预期'}'|

只想看看代码的主要问题是什么。

我试图单独隔开程序，以查看是否错过了某个地方的输入，但是找不到任何错误。

#include<iostream>
using namespace std;

class node

{
    public:
        string name,id;
        int age;
        node *next;
        void add();
        void takeout();
        void look();
        void display();

    node(string n,string i,int a)
    {
        name=n;
        id=i;
        age=a;
        next=NULL;
    }

};

class Linkedlist{
   private:
       node *list;

   public:
       Linkedlist(){
           list = NULL;
       }

void add() // adds the information for the linked list
{
    string s,i;
    int a;
    cout << "\nEnter the student's information below.\n";
    cout << "Student's Name : ";
    cin >> s;
    cout << "Student's ID : ";
    cin >> i;
    cout << "Student's Age : ";
    cin >> a;

    node *t = new node(s,i,a);

    //adding front
    t->next=list;
    list=t;
}

void takeout()
{
    string a;
    cout << "\nEnter the Student's ID so their info can be removed. \n";
    cout << "Student's ID : ";
    cin >> a;

    node *prev=NULL,*temp=list;
    while(temp!=NULL)
    {
        if(temp->id==a)
        {
           cout<<"Found.\n";
            break;
        }
        prev=temp;
        temp=temp->next;
    }
    if(temp==NULL)
    {
        cout<<"\nInformation not found.\n";
    }
    else if(prev==NULL)
    {
        cout<<"Delinked1\n";
        list=list->next;
    }
    else
    {
        cout<<"Delinked2\n";
        prev->next=temp->next;
    }
}

void look()
{
    string a;
    cout << "\nEnter Student's ID to search for their information.\n ";
    cout << "Student's ID : ";
    cin >> a;

    node *temp=list;
    while(temp!=NULL)
    {
        if(temp->id==a)
        {
        //diplyaing result
        cout << "\n------------------------------\n";
        cout << "Name :" << temp->name << endl;
        cout << "ID :" << temp->id << endl;
        cout << "Age :" << temp->age << endl;
        cout << "\n------------------------------\n";
        break;
        }

        temp=temp->next;
    }
    if(temp==NULL)
    {
        cout << "\nInformation on found.\n";
    }
}

void display()
{
    node *temp=list;
    if(temp==NULL)
        cout<<"\nLIST IS EMPTY---\n";
    while(temp!=NULL)
    {
        //displaying
        cout << "\n------------------------------\n";
        cout << "Name :" << temp->name << endl;
        cout << "Age :" << temp->age << endl;
        cout << "\n------------------------------\n";

        temp=temp->next;
    }
}

int main()
{
    Linkedlist list;
    cout << "Student Information (Linked List)\n\n";
    while(1)
    {
        int choice;
        cout << "\n1. Add a node." << endl;
        cout << "2. Delete a node." << endl;
        cout << "3. Search a node." << endl;
        cout << "4. Display a node." << endl;
        cout << "Enter your choice : ";
        cin >> choice;
        cout << endl;
        switch (choice)
        {
            case 1:
            {
                list.add();
                break;
            }
            case 2:
            {
                list.takeout();
                break;
            }
            case 3:
            {
                list.look();
                break;
            }
            case 4:
            {
                list.display();
                break;
            }
            default:
                cout << "Wrong choice!" << endl;
                break;
        }
    }
}

我知道代码的末尾应该显示什么，因为我在不得不更改输入之前就运行了它，但是现在由于这个错误，程序无法运行。

Answer 1

class Linkedlist{
  private:
    node *list;

  public:
    Linkedlist(){
        list = NULL;
    }

糟糕！...没有结束'}'

尽管没有任何要求，但我总是发现提供一致的格式，在表达式和大括号之间留有空格，这有助于我快速扫描文件并确认大括号平衡，例如

class Linkedlist {
  private:
    node *list;

  public:
    Linkedlist() {
        list = NULL;
    }
    ...
};      /* <== this is the missing closing-brace in your code */

实际上，您遇到的情况是您缺少该类的闭括号，该类包括下面的所有成员函数，例如

class Linkedlist {
  private:
    node *list;

  public:
    Linkedlist() {
        list = NULL;
    }

    void add() // adds the information for the linked list
    {
        ...
    void display()
    {
        node *temp=list;
        if(temp==NULL)
            cout<<"\nLIST IS EMPTY---\n";
        while(temp!=NULL)
        {
            //displaying
            cout << "\n------------------------------\n";
            cout << "Name :" << temp->name << endl;
            cout << "Age :" << temp->age << endl;
            cout << "\n------------------------------\n";

            temp=temp->next;
        }
    }
};      /* <== this is the actual missing closing-brace in your code */

一致的缩进将有助于识别该问题。添加结束'}'后，您的代码才编译。

在菜单上添加一个内容也很不错：

1. Add a node.
2. Delete a node.
3. Search a node.
4. Display a node.
5. Exit.                 // exit would be nice
Enter your choice :

如何在输入结尾处修复预期的}错误

1 个答案: