C++在 while 循环后添加一行代码会导致错误

我已经尽力寻找一个解决我具体问题的答案，但不幸的是，我无法找到一个满足我需求的答案。

我正在用c ++为我编写的语言编写汇编程序。编写汇编程序涉及两个类，这两个类导致了非常难以调试的问题。我的调试技术已经转移到添加和删除输出流命令，例如

std::cout << "TEST";

最终会破坏或修复程序。我正在使用的IDE是Xcode。

我正在处理的两个类是 LinkedList 类和 SymbolTable 类，我将其用作符号解析的哈希表。

LinkedList.h

#include <iostream>
using namespace std;
struct Node{
string data;
int address;
Node* next = nullptr;
};
class LinkedList{
private:
Node* main_ptr;
int length;
public:
LinkedList();
void insertNode(string, int);
void deleteNode(string);
void displayList();
bool contains(string, int* = nullptr);
int getLength();
~LinkedList();
};

链接列表.cpp

#include "LinkedList.h"
LinkedList::LinkedList(){
main_ptr = nullptr;
length = 0;
}
void LinkedList::insertNode(string data, int address){
Node* newNode = new Node;
newNode->data = data;
newNode->address = address;
if (!main_ptr){
main_ptr = newNode;
} else {
newNode->next = main_ptr;
main_ptr = newNode;
}
length++;
}
void LinkedList::deleteNode(string data){
if (main_ptr){
int current_length = length;
if (main_ptr->data == data){
main_ptr = main_ptr->next;
return;
}
Node* q = main_ptr;
Node* p = q;
q = q->next;
while (q){
if (q->data == data){
p->next = q->next;
length--;
return;
}
p = q;
q = q->next;
}
if (current_length == length) cout << "Node was not found" << endl;
} else {
cout << "List is empty, cannot delete node!" << endl;
}
}
void LinkedList::displayList(){
if (!main_ptr){
cout << "List is empty!n";
} else {
Node* temp = main_ptr;
while (temp){
cout << temp->data;
temp = temp->next;
}
cout << endl;
}
}
bool LinkedList::contains(string data, int* address){
if (main_ptr == nullptr) return false;
else {
Node* temp = main_ptr;
while(temp != nullptr){
if (temp->data == data) {
address = &(temp->address);
return true;
}
temp = temp->next;
}
return false;
}
}
int LinkedList::getLength(){
return length;
}
LinkedList::~LinkedList(){
if (main_ptr){
Node* q = main_ptr;
Node* p = q;
while (q){
q = q->next;
delete p;
p = q;
}
}
}

符号表.h

#include "LinkedList.h"
#include <iostream>
class SymbolTable{
private:
LinkedList table[701];
public:
SymbolTable();
void addEntry(string, int);
void printTable();
bool contains(string, int*);
int convertName(string);
};

符号表.cpp

#include "SymbolTable.h"
SymbolTable::SymbolTable(){
}
void SymbolTable::addEntry(string name, int memory){
int address = convertName(name);
table[address].insertNode(name, memory);
}
void SymbolTable::printTable(){
for (int i = 0; i < 701; i++)
table[i].displayList();
}
bool SymbolTable::contains(string name, int* memory){
return table[convertName(name)].contains(name, memory);
}
int SymbolTable::convertName(string name){
int aggregate = 1;
const char* c_name = name.c_str();
for (int i = 0; i < name.length(); i++){
aggregate *= (int)c_name[i];
}
return aggregate%701;
}

现在我的实际问题来了。以下是主要功能：

#include "Parser.h"
#include "SymbolTable.h"
using namespace std;
int main(int argc, const char * argv[]) {
ifstream inputFile;
ofstream outputFile;
inputFile.open("/Users/Azaldin/Desktop/nand2tetris/projects/06/max/Max.asm");
outputFile.open("/Users/Azaldin/Desktop/nand2tetris/projects/06/max/Max.hack");
Parser a(inputFile);
SymbolTable s;
int commandType = -1;
string command;
int a_position = 16;
int currentLine = 0;
while (a.hasMoreCommands()){
a.advance();
commandType = a.commandType();
command = a.symbol();
if (commandType == 0){
if (!s.contains(command, nullptr)){
s.addEntry(command, a_position);
a_position++;
}
}
if (commandType == 2){
//cout << command << endl;
if (!s.contains(command, nullptr)){
s.addEntry(command, currentLine);
//cout << command << endl;
}
}
currentLine++;
}
string x;  //<<<<<<<<<< ADDING THIS LINE BREAKS THE PROGRAM
cout << "Hi";
inputFile.close();
outputFile.close();
return 0;
}

在主函数中添加上面指向的行后，程序中断。 调试时，主线程出现以下问题：

线程 1：EXC_BAD_ACCESS(代码 = 1，地址 = 0x25fbfef80)

导致此问题的命令链：

1. 从主功能if (!s.contains(command, nullptr)){

2. return table[convertName(name)].contains(name, memory);从符号表中.cpp"包含"函数

3. if (temp->data == data) {来自 LinkedList .cpp "contains" 函数

链命令的其余部分指向字符串类 == 运算符，然后指向左侧的 .size() 函数。

谢谢！