-1

基本上我在这里有 2 个链表：list 和 distinct。有几组词早先已保存到“列表”结构中。打算编写一个程序，该程序将找到不同/唯一的单词并将其保存到“不同”结构中。这是我到目前为止基于我的指针概念得到的。但是，当我尝试打印“不同”时，程序崩溃:(如果我错了，请纠正我。

struct list {
char string[50];
struct list *next;
};

struct distinct {
char string[50];
struct distinct *next; 
};

void checkdistinct() { 

 list *ori = NULL;
 distinct *copy = NULL;
 distinct *check = NULL;

if(ori == NULL && copy == NULL) { //first time.
    ori = ori->next;
    copy = copy->next;
    copy = (distinct*)malloc(sizeof(distinct));
    strcpy(copy->string, ori->string);
    ori = ori->next;
    copy = copy->next;
}
else {}

while(ori!=NULL) {
    check = check->next;

   while(check != NULL) {
    if(strcmp(ori->string, check->string)!=0) {
        check = check->next;
    }
    else {
        ori = ori->next;
        check = NULL;
    }

 }

    //only compare same casing words, for now.
    copy = (distinct*)malloc(sizeof(distinct));
    strcpy(copy->string, ori->string);
    ori = ori->next;
    copy = copy->next;      
 }
}

当我尝试在 main 中打印时，它会崩溃:(如果您需要对代码的额外评论，请回复。谢谢！

4

2 回答 2

0

在您的代码中， distinct 不是变量的名称，而是结构的名称。您似乎误解了指针，希望这会有所帮助，尽管它与您的问题没有直接关系。

我省略了很多错误检查以使代码看起来更简单。

typedef struct listnode {
    char string[50];
    struct listnode *next;
} list_node;

typedef struct listbase {
    list_node *head;
    int numberOfElements;
} list;

/* Add a new string at the start of the list
*/
void ListPrepend(list *myList, char *myString) {
    list_node *newNode = malloc(sizeof *newNode); /* create node to store string */

    strcpy(newNode->string, myString); /* copy string into node */
    newNode->next = myList->head;      /* New node now followed by whole list */
    myList->head = newNode;            /* List now starts with new node */
    myList->numberOfElements++;
}

/* Add a new string at the end of the list
*/
void ListAppend(list *myList, char *myString) {
    list_node *newNode = malloc(sizeof *newNode), /* create node to store string */
              *currentNode = myList->head; /* pointer to node so we can find the end */

    strcpy(newNode->string, myString); /* copy string into new node */
    newNode->next = NULL;              /* Nothing following this node */

    if ( myList->head == NULL ) {
        myList->head = newNode; /* we didn't have a start node so assign it */
    } else {
        /* if there is a next node, move to it */
        while ( currentNode->next != NULL ) {
            currentNode = currentNode->next;
        }
        /* there is no next node so add new node on the end */
        currentNode->next = newNode;
    }
    myList->numberOfElements++;
}

/* Show the list in order head to tail
*/
void ListDisplay(list *myList) {
    list_node *currentNode = myList->head;

    while ( currentNode != NULL ) {
        printf("%s\n", currentNode->string);
        currentNode = currentNode->next;
    }
}

int main() {
    list distinct = {0}; /* Now there is a variable called distinct */
    char name[][20] = {"Lim Zheng Yue", "Monkey", "Dave"};

    ListAppend(&distinct, name[0]);
    ListAppend(&distinct, name[1]);
    ListPrepend(&distinct, name[2]);
    ListDisplay(&distinct);
}
于 2012-06-26T13:16:38.267 回答
0

这三行可能是罪魁祸首之一：

if(ori == NULL && copy == NULL) { //first time.
    ori = ori->next;
    copy = copy->next;

在这里检查 ifori和copyare NULL，然后立即取消引用这些NULL指针！

于 2012-06-26T12:22:41.577 回答