C编程strcat.asm not found错误调试

Question

我正在做家庭作业，一直在尝试调试我的程序，但无济于事。我试图读入一个输入文件，然后将每个字符添加到链接列表的末尾，但我的程序一直崩溃，并说找不到 strcat.asm，以及“0x0FA74127 (msvcr120d.dll) 中未处理的异常...... . writing location 0x00000000000000”，从这里查看其他问题来看，这似乎是 NULL 指针的问题。在处理这个单一问题 3 小时后，我向大家寻求帮助，谢谢。这是完整的代码:

    #include <stdlib.h>
#include <stdio.h>
#include <string.h>


#define LENGTH 80

struct boggleDataNode {
    char data[3];
    struct boggleDataNode *nextData;
};

void readData(struct boggleDataNode **);
struct boggleDataNode* makeNode(char *);
void display(struct boggleDataNode *);

int main() {
    struct boggleDataNode * head = NULL;
    readData(&head);
    display(head);
}

void readData(struct boggleDataNode **headRef){
    //initializing variables including
    //opening the input file
    char dataLine[LENGTH];
    char *data;
    char *fileName = "BoggleData.txt";

    FILE *filePointer;

    printf("Trying to open file %s\n", fileName);
    filePointer = fopen(fileName, "r"); //read mode
    printf("Successfully opened file %s\n", fileName);

    if (filePointer == NULL){
        perror("Error while opening file. \n");
        exit(0);
    }

    //loop until find end of file
    while (fgets(dataLine, LENGTH, filePointer) != NULL){
        for (char *tok = strtok(dataLine, " "); tok; tok = strtok(NULL, " "))
        {
            data = tok;
            printf("data = %s\n", tok);
            if (*headRef == NULL){
                *headRef = makeNode(data);
                head = *headRef;
            }
            else{
                head->nextData = makeNode(data);
                head = head->nextData;
            }
        }
    }

    fclose(filePointer);

}//close readData

struct boggleDataNode* makeNode(char *data){
    struct boggleDataNode* temp = (struct boggleDataNode*) malloc(sizeof(struct boggleDataNode));
    strcpy(temp->data, data);
    temp->nextData = NULL;
    return temp;

    /*
    //allocate node
    struct boggleDataNode* temp = (struct boggleDataNode*) malloc(sizeof(struct boggleDataNode));
    struct boggleDataNode* right = (struct boggleDataNode*) malloc(sizeof(struct boggleDataNode));

    if ((*headRef) == NULL){
    strcpy((*headRef)->data, data);
    (*headRef)->nextData = NULL;
    }
    else{
    strcpy(temp->data, data);
    temp->nextData = NULL;

    // ======== The program appears to break here ================
    right = (*headRef);
    while (right->nextData != NULL)
    right = right->nextData;

    right->nextData = temp;
    right = temp;
    right->nextData = NULL;
    }
    }  */
}

void display(struct boggleDataNode *headRef){

    struct boggleDataNode *helper = headRef;

    if (helper == NULL){
        return;
    }
    else{
        printf("============================================\n");
        printf("Node #        Data\n");
        printf("============================================\n");

        int counter = 1;

        while (helper != NULL){
            printf("%5d \t %2s\n", counter++, helper->data);
            helper = helper->nextData;
        }
    }
    printf("\n");
}

这是输入文件

D R L X E I
C P O H S A
N H N L Z R
W T O O T A
I O S S E T 
N W E G H E
B O O J A B
U I E N E S
P S A F K F
I U N H M Qu
Y R D V E L
V E H W H R
I O T M U C
T Y E L T R
S T I T Y D
A G A E E N

Answer 1

让我们在 C 中尝试更面向对象的方法。

1. 将 main 的正文更改为:

   struct boggleDataNode * head = NULL;
   readData(&head);
   display(head);
   

   NULL 很好地表示一个空链表。

2. 将 readData 定义的开头更正为(注意两个星号):

   void readData(struct boggleDataNode **headRef){
   

   这需要与您之前在程序中声明的原型(prototype)相匹配。

3. 将 addEntry 的声明/原型(prototype)替换为

   struct boggleDataNode* makeNode(char *);
   

4. 并将addEntry的定义替换为

   struct boggleDataNode* makeNode(char *data){
       struct boggleDataNode* temp =
           (struct boggleDataNode*) malloc(sizeof(struct boggleDataNode));
       strcpy(temp->data, data);
       temp->nextData = NULL;
       return temp;
   }
   

   请注意，这种方法更容易推理。它将分配内存，复制字符串数据，并留下指向下一个节点的链接，表明它没有指向任何东西。这基本上是后 C 语言中构造函数的工作。请注意，您在这里分配了内存，但稍后您需要释放该内存。

5. 最后，将 readData 方法中的 addEntry 调用替换为:

   if (*headRef == NULL) {
       *headRef = makeNode(data);
       head = *headRef;
   } else {
       head->nextData = makeNode(data);
       head = head->nextData;
   }
   

   此外，您需要在 readData 方法中声明 struct boggleDataNode * head = NULL;。