如何从文件中填充链表

Question

我正在尝试填充从文件中读取的链接列表。我一直在尝试使用strtok() 来分隔使用" " 作为分隔符的字符串。当我调用我的addEntry() 函数时，它只是将每个字符串的第一个字母添加到一个新节点。我意识到这可能是一个简单的疏忽，所以请原谅我的无知，因为我对编码还是很陌生。

我遇到问题的具体代码部分是：

void readData(struct boggleDataNode **headRef){
    //initializing variables including
    //opening the input file
    int counter = 96;
    int i = 0;
    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){
        //I feel like i should be using a nested loop here but I can't figure out how to do it 
        printf("dataLine = %s\n", dataLine);
        data = strtok(dataLine, " ");
        printf("data = %s\n", data);
        //fgets(data, 3, filePointer);
        addEntry(headRef, data);
        //nested loop should end here
    }
}

我的输出只有 16 个节点，每行的第一个字母，当它应该是 96 个节点长时。 我正在读取的文件是：

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

---

如果需要完整代码：

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

#define LENGTH 80

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

struct boggleDieSideNode {
    char dieSideData[3];
    struct boggleDieSideNode *nextSide;
};

void readData(struct boggleDataNode **);
void addEntry(struct boggleDataNode **, char *);
void display(struct boggleDataNode *);

int main() {

    int counter = 0;

    struct boggleDataNode * head = NULL;
    struct boggleDieSideNode *head1 = NULL;
    readData(&head);
    display(head);

    system("pause");
    return 0;
}

void readData(struct boggleDataNode **headRef){
    //initializing variables including
    //opening the input file
    int counter = 96;
    int i = 0;
    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){
        printf("dataLine = %s\n", dataLine);
        data = strtok(dataLine, " ");
        printf("data = %s\n", data);
        //fgets(data, 3, filePointer);
        addEntry(headRef, data);
    }

    fclose(filePointer);

}//cose readData

void addEntry(struct boggleDataNode **headRef, char *data){

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

    //put in data
    strcpy(temp->data, data);

    // link the old list off the new node
    temp->nextData = (*headRef);

    // move the head to point to the new node
    (*headRef) = temp;
}

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");
    system("pause");
}

Answer 1

您需要一个嵌套循环是绝对正确的。

strtok 需要这样调用：

for (char *tok = strtok("input", " "); tok; tok = strtok(NULL, " "))
{
    /* use tok */;
}

Answer 2

• 如果您只对单个字符感兴趣，则无需阅读完整的行（并将它们切割成单个字符）
• 因为你只对单个字符感兴趣，所以结构中的.data元素不需要是char data[3]
• 读取文件的函数可以将文件名作为参数
• 并且该函数可以返回它已读取的列表，而不是返回 void 并将结果通过指针指针传递回调用方。

---

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

struct boggleNode {
    struct boggleNode *next;
    char data;
    };

struct boggleNode * readboggle(char *name);

int main (int argc, char **argv)
{
struct boggleNode *bp;

if (!argv[1]) return 0;

bp = readboggle( argv[1] );

for ( ; bp; bp = bp-> next) {
        printf(" %c", bp->data);
        }

printf("\n" );
return 0;
}

struct boggleNode * readboggle(char *name)
{
struct boggleNode *ret=NULL, **bpp;
FILE *fp;
int ch;

fp = fopen (name, "r" );
if (!fp) return NULL;

ret= NULL;
bpp = &ret;
while(1)        {
        ch = getc(fp);
        if (ch == EOF) break;
        if (ch < 'A' || ch > 'Z') continue;
        *bpp = malloc (sizeof **bpp);
        (*bpp)->data = ch;
        (*bpp)->next = NULL;
        bpp = &(*bpp)->next;
        }
fclose (fp);
return ret;
}