c++ 链表中有关指针问题的求教

#define _CRT_SECURE_NO_WARNINGS；
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include <string>
#include "head.h"
#include <vector>

using namespace std;

char KeyWord[] = "保留字";
char ID[] = "标识符";
char keyWord[50][100] = { "void","main","printf","if","else","return","int" };
int currentNum = 0;
char entry[40];
FILE* cstream, * outstream;
ChainList keyWordList;
ChainList idList;

int move(int s, char ch);
void AutoForId(FILE* cstream, FILE* outstream);
int getLength(char ch[]);

int main()
{
	ChainListNode* temp;
	while (strcmp("",keyWord[currentNum])!=0)
	{
		if (keyWordList.Insert(keyWord[currentNum], currentNum, KeyWord))
			printf("%s\n", "插入成功！");
		else
			printf("%s\n","插入失败！");
		currentNum++;
	}
	currentNum = 0;

	if ((cstream = fopen("d:/sample.txt", "r")) == NULL)
	{
		printf("Failed to open sample.txt!");
		exit(0);
	}

	if ((outstream = fopen("d:/text.txt", "w")) == NULL)
	{
		printf("Failed to open text.txt");
		exit(0);
	}
	
	AutoForId(cstream, outstream);

	fclose(cstream);
	fclose(outstream);

	system("pause");
}

void AutoForId(FILE* cstream, FILE* outstream)
{
	char ch;
	int currentNum = 0;
	int s0 = 0;
	int sEnd = 2;
	int s = s0;
	
	memset(entry,'\0',sizeof(entry));
	ch = fgetc(cstream);
	while (ch != EOF)
	{
		s = move(s, ch);

		if (s == sEnd)
		{
			//if (keyWordList.Search(entry) && !idList.Search(entry))
				{
					idList.Insert(entry, currentNum, KeyWord);
					printf("%s\n",entry);//fprintf(outstream, "%d %s %s\n", currentNum, KeyWord, entry);
					currentNum++;
				}
			/*else if (!keyWordList.Search(entry) && !idList.Search(entry))
				{
					idList.Insert(entry, currentNum, ID);
					fprintf(outstream, "%d %s %s\n", currentNum, ID, entry);
					currentNum++;
				}*/
			memset(entry, '\0', sizeof(entry));
			s = s0;
		}
		ch = fgetc(cstream);
	}
}

int move(int s, char ch)
{
	if (((int)ch >= 65 && (int)ch <= 90) || ((int)ch >= 97 && (int)ch <= 122) && s == 0)
	{
		entry[getLength(entry)] = ch;
		return 1;
	}
	else if (s == 0)
		return 0;
	else if (((((int)ch >= 65 && (int)ch <= 90) || ((int)ch >= 97 && (int)ch <= 122) || ((int)ch >= 48 && (int)ch <= 57))) && s == 1)
	{
		entry[getLength(entry)] = ch;
		return 1;
	}
	else if(s==1)
		return 2;
}

int getLength(char ch[])
{
	int length = 0;
	while (ch[length] != '\0')
		length++;
	return length;
}



head.h
#pragma once
#include <string.h>
#include<stdio.h>

struct Data
{	
	public:
	char* name;
	int num;
	char* type;
};

class ChainListNode
{
	public:
		Data data;
		ChainListNode* nextNode;
};

class ChainListHeadNode
{
	public:
		ChainListNode* nextNode;
};

class ChainList
{
	public:
		ChainListHeadNode* firstNode;

		ChainList()
		{
			length = 0;
			firstNode = new ChainListHeadNode;
			firstNode->nextNode= nullptr;
		}

		~ChainList()
		{
			ChainListNode* current;
			current = firstNode->nextNode;
			while (firstNode->nextNode)
			{
				current = current->nextNode;
				delete firstNode->nextNode;
				firstNode->nextNode = current;
			}
			delete firstNode;
		}

		bool Insert(char *newName,int newNum,char* newType)
		{
			ChainListNode* newNode = new ChainListNode;
			newNode->data.name = newName;
			newNode->data.num = newNum;
			newNode->data.type = newType;

			newNode->nextNode = firstNode->nextNode;
			firstNode->nextNode = newNode;
			length++;

			return true;
		}

		bool Search(char *searchKey)
		{
			ChainListNode* current = firstNode->nextNode;
			while (current && strcmp(searchKey,current->data.name)!=0)
				current = current->nextNode;
			if (current)
				return true;
			else
				return false;
		}

		void Display()
		{
			ChainListNode* current = firstNode->nextNode;

			while (current)
			{
				printf("%s\n",current->data.name);
				current = current->nextNode;
			}
		}

		int getListLength()
		{
			return length;
		}

	private:
		int length ;
};

这是老师布置的一个识别简单代码中标识符自动机的代码。我构造了一个保留字链表，在之后自动机代码段执行的过程中，被注释掉的if语句中的Search函数除了第一个void值，之后对所有entry执行的返回值都是true，也就是说我的第二个链表只有void一个元素。真心求教。

void main()
{
	int i,j,sum;
	i=j=1;
	sum=0;
	sum=i+j;
	printf("%d\n",sum);
}

你的最大问题出在class ChainList的成员函数bool Insert(char *newName,int newNum,char* newType)

			newNode->data.name = newName;
			newNode->data.num = newNum;
			newNode->data.type = newType;

改为

		newNode->data.name = _strdup(newName);
		newNode->data.num = newNum;
		newNode->data.type = _strdup(newType);

定义在函数体外的变量均为静态变量，地址不变，而你对变量改变时，与其相同地址的变量都会跟着变。

另外你的函数还有其它问题，如文件路径中“\"要用‘\\’

其它问题不一一列举了，将源码给你：

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include <string>
#include "head.h"
#include <vector>

using namespace std;

char KeyWord[] = "保留字";
char ID[] = "标识符";
char keyWord[50][100] = { "void","main","printf","if","else","return","int" };
int currentNum = 0;
char entry[40];
FILE* cstream, * outstream;
ChainList keyWordList;
ChainList idList;

int move(int s, char ch);
void AutoForId(FILE* cstream, FILE* outstream);
int getLength(char ch[]);

int main()
{
	ChainListNode* temp;
	while (strcmp("", keyWord[currentNum]) != 0)
	{
		if (keyWordList.Insert(keyWord[currentNum], currentNum, KeyWord))
			printf("%s\n", "插入成功！");
		else
			printf("%s\n", "插入失败！");
		currentNum++;
	}
	currentNum = 0;

	if ((cstream = fopen("d:\\sample.txt", "r")) == NULL)
	{
		printf("Failed to open sample.txt!");
		exit(0);
	}

	if ((outstream = fopen("d:\\text.txt", "w")) == NULL)
	{
		printf("Failed to open text.txt");
		exit(0);
	}

	AutoForId(cstream, outstream);

	fclose(cstream);
	fclose(outstream);

	system("pause");
}

void AutoForId(FILE* cstream, FILE* outstream)
{
	char ch;
	int currentNum = 0;
	int s0 = 0;
	int sEnd = 2;
	int s = s0;

	memset(entry, '\0', sizeof(entry));
	ch = fgetc(cstream);
	while (ch != EOF)
	{
		s = move(s, ch);

		if (s == sEnd)
		{
			if (keyWordList.Search(entry) && !idList.Search(entry))
			{

				idList.Insert(entry, currentNum, KeyWord);
				printf("%s\n", entry);
				fprintf(outstream, "%d %s %s\n", currentNum, KeyWord, entry);
				currentNum++;

			}
			else if (!keyWordList.Search(entry) && !idList.Search(entry))
			{
				idList.Insert(entry, currentNum, ID);
				printf("%s\n", entry);
				fprintf(outstream, "%d %s %s\n", currentNum, ID, entry);
				currentNum++;
			}
			memset(entry, '\0', sizeof(entry));
			s = s0;
		}
		ch = fgetc(cstream);
	}
}

int move(int s, char ch)
{
	if (((int)ch >= 65 && (int)ch <= 90) || ((int)ch >= 97 && (int)ch <= 122) && s == 0)
	{
		entry[getLength(entry)] = ch;
		return 1;
	}

	if (((int)ch >= 65 && (int)ch <= 90) || ((int)ch >= 97 && (int)ch <= 122) || ((int)ch >= 48 && (int)ch <= 57) && s == 1)
	{
		entry[getLength(entry)] = ch;
		return 1;
	}

	if (s == 1)
		return 2;

	return 0;
}

int getLength(char ch[])
{
	int length = 0;
	while (ch[length] != '\0')
		length++;
	return length;
}



head.h

#pragma once
#include <string.h>
#include<stdio.h>

struct Data
{
public:
	char* name;
	int num;
	char* type;
};

class ChainListNode
{
public:
	Data data;
	ChainListNode* nextNode;
};

class ChainListHeadNode
{
public:
	ChainListHeadNode() { nextNode = nullptr; }
public:
	ChainListNode* nextNode;
};

class ChainList
{
public:
	ChainListHeadNode* firstNode;

	ChainList()
	{
		length = 0;
		firstNode = new ChainListHeadNode;
		firstNode->nextNode = nullptr;
	}

	~ChainList()
	{
		ChainListNode* current;
		current = firstNode->nextNode;
		while (firstNode->nextNode)
		{
			current = current->nextNode;
			delete firstNode->nextNode;
			firstNode->nextNode = current;
		}
		delete firstNode;
	}

	bool Insert(char* newName, int newNum, char* newType)
	{
		ChainListNode* newNode = new ChainListNode;
		newNode->data.name = _strdup(newName);
		newNode->data.num = newNum;
		newNode->data.type = _strdup(newType);
		newNode->nextNode = firstNode->nextNode;
		firstNode->nextNode = newNode;
		length++;
		return true;
	}

	bool Search(char* searchKey)
	{
		ChainListNode* current = firstNode->nextNode;
		for (int i = 0; i < length; i++)
		{
			if (strcmp(searchKey, current->data.name) == 0)
				return true;
			if (current->nextNode == nullptr)
				return false;
			current = current->nextNode;
		}
		return false;
	}

	void Display()
	{
		ChainListNode* current = firstNode->nextNode;

		while (current)
		{
			printf("%s\n", current->data.name);
			current = current->nextNode;
		}
	}

	int getListLength()
	{
		return length;
	}

private:
	int length;
};

在D:盘下自定义一个文本文件sample.txt，内容为“void","main","printf","if","else","return","int" ，可用于测试

插入成功！
插入成功！
插入成功！
插入成功！
插入成功！
插入成功！
插入成功！
void
main
printf
if
else
return
int
请按任意键继续. . .