链表C++赛格错误

我正在尝试从头开始制作一个简单的链表，供另一个类使用。错误似乎是有时头部未设置为 NULL。我说有时之前它不会一直出错。它没有出错的时候，它会转到 else 语句。注意我只添加 1 个字符串。也许你们能发现一些我没有看到的东西，干杯！

LinkedList.h：

#include <string>
#include "Link.h"
using namespace std;
class LinkedList {
  Link *head;
public:
  LinkedList();
  void addFront(string key);
  void printList();
  //void addBack(string *);     
};

链接列表.cpp：

#include <cstring>
#include <string>
#include <iostream>
#include <cstdlib>
#include <cstdio>
#include "LinkedList.h"
using namespace std;
LinkedList::LinkedList() {
   head = NULL;
}
void LinkedList::addFront(string key) {
  //creates the new list segment                                                
  Link *l = new Link(key);
  cout << "Made new Link " << key << endl;
  // if the list is empty                                                 
  if (head == NULL){
    cout << "Going to set Head " << key << endl;
    head = l;
    cout << "Set Head to new link " << key << endl;
 }                                            
  else {             
     cout << "Else statement " << key << endl;                  
    l->setNext(head);
    head = l;
  }
}
void LinkedList::printList() {
 //Check if list is empty
  if(head == NULL)
   cout << "NULL" << endl;
  else {
   Link *l = head; 
   for(;l != NULL; l=l->getNext())
     cout << l->getValue() << endl;
  }

}
// void LinkedList::addBack(string *f) {
//   Link *l = new Link(f);
// }

链接.h

#include <cstdlib>
#include <cstring>
#include <string>
using namespace std;
class Link {
string key;
Link *next;
public:
    Link(string key);
    void setValue(char);
    void setNext(Link *next);
    string getValue();
    Link *getNext();
    void printList();
};

链接.cpp

#include <cstdlib>
#include <string>
#include <iostream>
#include "Link.h"
using namespace std;
Link::Link(string key) {
    this->key = key;
next = NULL;
}
void Link::setNext(Link *l) {
cout << "setting new link "<<endl;
next = l;
cout<< "New link was set" << endl;
}
string Link::getValue() {
return key;
}
Link *Link::getNext() {
return next;
}

哈希.h

#include <iostream>
#include <cstring>
#include <string>
#include "LinkedList.h"
using namespace std;
class Hash{
    //100 slot array for hash function
    LinkedList *hashFN[100];
    //preset prime number                                                               
  int prime = 101;
    int key;
  unsigned int location;
public:
    //Note: Both the key & values are the same 
    void insert(string key, string value);
    // void deleteItem(int key);
    // char* find(int key);

};

哈希.cpp：

#include <iostream>
#include <cstring>
#include <string>
#include "Hash.h"
using namespace std;
void Hash::insert(string k, string v){
    //Get Hash for argv[2] aka value                                                  
  size_t key = std::hash<string>()(k);
   unsigned int location;
//check 1                                                                         
  cout << "Hash: " << key << endl;
  //Find location
  location = key % prime;
  //check 2                                                                         
  cout << "Mod 101 Hash: " << location << endl;
    hashFN[location]->addFront(k);
    cout << "Success!" << endl;
}
// void Hash::deleteItem(int key){
//  return;
// }
// char* Hash::find(int key){
//  return;
// }

主.cpp

#include <iostream>
#include <functional>
#include <string>
#include <cstring>
#include <cstdlib>
#include <cstdio>
#include "Hash.h"                                                                   
using namespace std;
int main(int argc, char *argv[]) {
  Hash HashTable;                                                                   

  string Insert = string("insert");
  string Delete = string("delete");
  string Find   = string("find");
  string Argv(argv[2]);  //Makes the argv[2] into string type
  // check for Request & string parameters                                            
  if(argc != 3) {
    cout << "Run program with 2 parameters. [Lower Case]" << endl;
    cout << "[1] insert, find, or delete" << endl;
    cout << "[2] string" << endl;
    exit(1);
  }
  //Check for "insert"                                                                
  if(strcmp(argv[1], "insert") == 0) {

  HashTable.insert(Argv, Argv);                                                
  }
  return 0;
}