C ++分段错误

Question

我正在尝试编译我的代码，但是一旦我尝试使用 InsertNode，我就会收到一个分段，并且程序崩溃了。请帮助

#include <iostream>
#include "Link.h"

using namespace std;

Node *createNode (){

  Node *newNode = new Node;
  cout<<"Enter your first name"<<endl;
  cin >> newNode->firstName;
  cout<<"Enter your last name"<<endl;
  cin>>newNode->lastName;
  cout <<"Enter your ID Number"<<endl;
  cin>>newNode->idNumber;
  newNode->next=NULL;
  return newNode;
}

Node *insertNode (Node *list){
Node *NewNode = createNode();
  //Node *NewNode = new Node;
 // NewNode= createNode();

  if(list == NULL){
list=NewNode;
  }
 else{
Node *tmp = list;
while(tmp->next!=NULL)
  tmp = tmp->next;
tmp->next=NewNode;
 }
  return list;
}

Node *searchNode (Node *list){

  bool found=false;
  Node *tmp=NULL;
  int ID;

  cout << "Enter the ID you wish to search for: "<< endl;
  cin >> ID;

  if(list==NULL){
    cout << "List is empty"<<endl;
    return 0;
  }

  while(list->next!=NULL){
    if(ID == (list-> idNumber)){
      tmp=list;
      found=true;
    }

  }
  if(found=false){
    cout<<"Not found"<<endl;
    return 0;
  }

  return tmp;
}

Node *deleteNode (Node *list){

    int ID;

  if(list==NULL){
    cout <<"The list is empty"<<endl;
    return 0;
  }
  cout << "Enter the ID number you wish to delete:" << endl;
  cin >> ID;
  if(list->idNumber==ID){

    Node *temp;

    temp=list->next;

    //free(list);

    return temp;
  }

  list->next = deleteNode(list->next);

  return list;
}

void printList(Node *list){

  Node* tmp=list;

  if(tmp==NULL){
    cout<<"The list is empty"<<endl;
  }

  cout<< tmp-> firstName<<endl;
  cout << tmp->lastName<<endl;
  cout <<tmp->idNumber<<endl;
}

提前感谢您的帮助

给他们一个菜单，用于调用这些功能中的任何一个添加我的主要内容只是为了向您展示

#include "Link.h"
#include <iostream>

using namespace std;

void DisplayMenu();
int main(){

  int answer=0;
  Node *NewNode = new Node;
  //NewNode = NULL;
  do{
    DisplayMenu();
    cin >> answer;
 if(answer==1){
     insertNode(NewNode);
 }
 else if(answer==2){
 deleteNode(NewNode);
 }
 else if(answer==3){
 printList(NewNode);
 }
 else if(answer==4){
 searchNode(NewNode);
 }
 else if(answer==5){
   cout << "Goodbye" << endl;
 }
  }while(answer!=5);





  return 0;


}

void DisplayMenu(){

  cout<< "1. Insert a node"<<endl;
  cout<<"2. Delete a node"<<endl;
  cout<<"3. Print List"<<endl;
  cout<<"4. Search a node-search a node and print information for a     student."<<endl;
  cout<<"5. Quit the program"<<endl;
}

Answer 1

Node.next 永远不会初始化为 null。

这会导致 insertNode() 出现问题：

while(tmp->next!=NULL)    <---- here
  tmp = tmp->next;

Answer 2

试试这个代码，看看你能不能看出区别

int main(){

      int answer=0;
      Node *list= NULL;    //<---- note list variable renamed to 'list' and initialized to null
      //NewNode = NULL;
      do{
        DisplayMenu();
        cin >> answer;
     if(answer==1){
         list = insertNode(list);     //<---- note added equals
     }
     else if(answer==2){
     deleteNode(list);
     }
     else if(answer==3){
     printList(list);
     }
     else if(answer==4){
     searchNode(list);
     }
     else if(answer==5){
       cout << "Goodbye" << endl;
     }
      }while(answer!=5);


      return 0;


    }

C ++分段错误

c++ Segmentation fault

c++

linked-list