Question

我在使用这段代码时遇到了一些麻烦。当我在添加到列表后尝试打印列表时，它只打印最后一个元素。

* list，* temp和* new_node在本地声明。

if(list == NULL && new_node != NULL){
        fprintf(fp1, "\r\nNew node1: %s %s %d %ld %d", new_node->op, new_node->name, new_node->tag, new_node->msgsize, new_node->weight);
        list = (struct  vertex*)malloc(sizeof(struct vertex));
        list->name = new_node->name;
        list->next = NULL;
        list_of_vertices[rank] = list;
        printf("changin list head\n");
        //temp = list->next;
    }
    else{
        if(new_node != NULL){
            temp = list;
            while(temp){
                temp = temp->next;
            }
            temp = (struct vertex*)malloc(sizeof(struct vertex));
            temp->name = new_node->name;
            temp->next = NULL;
            fprintf(fp1, "\r\nNew node: %s %s %d %ld %d", temp->op, temp->name, temp->tag, temp->msgsize, temp->weight);
        }
    }

编辑：以下代码也不起作用。它每次都会更改list的值，但我只进入if条件设置一次列表。

while(!feof(fp)){
    fgets(read_line, 100, fp);
    /*new node created by tokenizing string */
    if(list == NULL && new_node != NULL){
        fprintf(fp1, "\r\nNew node1: %s %s %d %ld %d", new_node->op, new_node->name, new_node->tag, new_node->msgsize, new_node->weight);
        list = (struct  vertex*)malloc(sizeof(struct vertex));
        list->name = new_node->name;
        list->next = NULL;
        printf("list head\n %s", list->op); //prints only once when first line from file read
    }
    if(list != NULL)
        printf("list head changed\n %s", list->name); // prints the name from the current read line.
}

Answer 1

更改

while(temp){
  temp = temp->next;
}

temp = (struct vertex*)malloc(sizeof(struct vertex));

到

while(temp->next){
  temp = temp->next;
}

temp->next = (struct vertex*)malloc(sizeof(struct vertex));
temp = temp->next;

Answer 2

修正了问题。我没有复制字符串值，而是使用指针（即a = b而不是strcpy（a，b），其中a和b是char数组）

头指针不断改变链表中的位置

2 个答案: