我尝试初始化一个名为initAmigo的queueADT指针。显然，如果结构没有为（void * data）指定
，我永远不会创建一个我无法在节点结构中的void *数据中放入任何数据的原因：
Asuumption 1：取走void *数据并说出User_struct（来自.h文件）
假设2：RegisteredData不应该是指针，因为que_Insert中的参数要求指针）
假设3：在AddUser函数中，que_insert（initAmigo，registeredData）;要插入void * data节点的registeredData实际上是指向结构
的指针让队列引用为void *会产生以下错误：
amigonet.c: In function 'findUser':
amigonet.c:247:21: warning: dereferencing 'void *' pointer [enabled by default]
if (currNode->data->name == name) { //If front is the name being searched
^
amigonet.c:247:21: error: request for member 'name' in something not a structure or union
amigonet.c:253:22: warning: dereferencing 'void *' pointer [enabled by default]
if (currNode->data->name == name ) {
.c文件只需要创建一个用户队列结构（QueueADT initAmigo）
typedef struct node {
//name of data userStruct (just for referencing)
void* data;
struct node *next;
}node;
struct queueStruct {
struct node *front; /* pointer to front of queue */
struct node *rear; /* pointer to rear of queue */
int (*cmprFunc)(const void*a,const void*b); /* The compare function used for insert */
};
typedef struct queueStruct *QueueADT; //typedef inserted for pointers,
//name is QueueADT
#define _QUEUE_IMPL_
#include "queueADT.h"
/// create a queue that is either sorted by cmp or FIFO
//function with two void
QueueADT que_create( int (*cmp)(const void*a,const void*b) ) {
QueueADT new;
new = (QueueADT)malloc(sizeof(struct queueStruct)); //NOTE: NO POINTERS HERE
//use pointers in Single lines
if (cmp == NULL) {
new->front = NULL;
new->rear = NULL;
new->cmprFunc = NULL;
} else {
new->cmprFunc = cmp;
new->front = NULL;
new->rear = NULL;
}
return ( new );
}
//free the queue once the nodes have been cleared from the queue
void que_destroy( QueueADT queue ) {
if ( queue->front == NULL ) {
free(queue);
} else {
que_clear(queue);
free(queue);
}
}
//passes a real pointer for dynamic allocation
//set a temp to the front to be deleted, then front becomes the next and delete the temp
void que_clear( QueueADT queue ) {
while (queue->front->next != NULL) {
struct node *temp;
temp = (struct node*)malloc(sizeof(struct node));
temp = queue->front;
queue->front= queue->front->next;
free(temp);
}
}
//if the cmpr function returns a positive then put in in before the b node in cmp(curr, temp)
void que_insert( QueueADT queue, void *data ) {
struct node *temp;
temp = (struct node*)malloc(sizeof(struct node));
temp->data= data;
temp->next = NULL;
node *currNode; //simply a pointer
currNode = queue->front;
if ( queue->front != NULL ) { //+1 or more in Q
if ( queue->cmprFunc == NULL ) { //if the cmp_func is FIFO
queue->rear->next = temp;
queue->rear= temp;
queue->rear->next=NULL;
if ( queue->front == queue->rear ) {
currNode->next = temp;
queue->rear = temp;
temp->next= NULL;
}
} else {
while ( currNode->next != NULL ){ //2 or more
if (( (*(queue->cmprFunc))(currNode->data, temp->data) >= 0
&& ( currNode == queue->front)) ) {
temp->next = currNode;
queue->front=temp;
break;
}
if (( (*(queue->cmprFunc))(currNode->next->data, temp->data) >= 0 ) ) {
temp->next = currNode->next;
currNode->next = temp;
break;
} else {
currNode = currNode->next; //move past front and possibly rear
if (currNode->next == NULL ) { //currNode is rear of queue
currNode->next = temp;
queue->rear = temp;
temp->next = NULL;
break;
}
//exit_failure
}
}
if ( queue->front == queue->rear ) { //exactly 1 node in queue
if (( (*(queue->cmprFunc))(currNode->data, temp->data) >= 0 ) ) {
temp->next = queue->front;
queue->front = temp;
} else {
queue->front->next = temp;
queue->rear = temp;
}
}
}
} else {
queue->front = temp;
queue->rear= queue->front;
queue->front->next= queue->rear->next = NULL;
}
}
//removes the front
void *que_remove( QueueADT queue ) {
if ( queue->front != NULL ) { //if the size of queue is greater than 1
node *currNode; // dont make new node, pointer
currNode = queue->front;
void *data = currNode->data;
if ( queue->front == queue->rear ) { //if size of queue is 1
free(currNode);
queue->front = queue->rear = NULL; //set both to NULL
} else {
queue->front= currNode->next;
free(currNode);
}
return data;
}
return NULL;
}
bool que_empty( QueueADT queue ) {
if ( queue->front == NULL ) {
return true;
} else {
return false;
}
}
QueueADT initAmigo;
//struct queueStruct *initAmigo
//QueueADT initAmigo;
//make a Queue with front and rear
//compare function with A-Z
struct Friends_struct {
struct queueStruct *amigos_Queue;
};
void create_amigonet() {
//makes the same thing as que_Create
//(Friends)malloc(sizeof(struct Friend_struct));
initAmigo = que_create(NULL);
printf("%lu Founded size of an.c\n\n\n\n\n\n\n\n\n\n\n", sizeof(initAmigo));
}
//The add user will find a new user and make the name of the user to a amigonet
//add Usernode to queue initAmigo
//make sure set to first and display queue
void addUser( const char *name ) {
//create Usernode and void *data (user w/ friends)
//check to see if User already exists
if ( findUser(name) != NULL) {
return;
}
//create data for node, by initializing memorry for a userStruct
struct User_struct *registeredData;
registeredData = ( struct User_struct* )malloc(sizeof(struct User_struct)); //first user Data
registeredData->name = name;
//create a Friends
//put this in file create F
struct Friends_struct *initAmigos;
initAmigos = (struct Friends_struct*)malloc(sizeof(struct Friends_struct)); //NOTE: NO POINTERS HERE
//set Friends list to Null
initAmigos->amigos_Queue = que_create( NULL );
//put User with empty Friends struct
registeredData->amigos = initAmigos;
//void que_insert( QueueADT queue, void *data )
que_insert( initAmigo , registeredData);
printf("%s User was inerted \n", name);
}
//Find a user in the init Amgio
//start at front as temp, go to next until name found
User *findUser( const char *name ) {
struct node *currNode;
currNode = initAmigo->front;
printf("%lu Founded size of an.c\n\n\n\n\n\n\n\n\n\n\n", sizeof(initAmigo));
if ( initAmigo->front == NULL ) {
return NULL;
} else {
if (currNode->data->name == name) { //If front is the name being searched
return currNode->data;
}
//Loop after front
while ( currNode->next != NULL ) {
currNode = currNode->next;
if (currNode->data->name == name ) {
return currNode->data;
}
}
node *rear = currNode;
if (rear->data->name == name ) {
return rear->data;
}
}
//User Not Founded
return;
}
#if 0
void addAmigo( User *user, User *amigo ) {
//check to see if node exits within friends
//go to use friends list
//traverse the node, check data for amigo->name == data->name
if ( user->amigos->amigos_Queue->front != NULL ) {
node *currNode = user->amigos->amigos_Queue->front;
if ( currNode->data->name == amigo->name ) {
return ;
} else {
//loop to determine if User friend queue front to rear has amigo already
while ( currNode->next != NULL ) {
currNode = currNode->next;
if (currNode ->data->name == amigo->name) {
return;
}
}
}
}
que_insert( user->amigos->amigos_Queue, amigo);
}
void removeAmigo( User *user, User *ex_amigo) {
//Pre Condition: Amgio exists in user
//go to user
//set user as currNode
//either create a function in queueADT remove
// use a prev and curr and next and traverse, remove, connect
//preconditions: front is not examigo
// rear is not examigo
// amigo is friend of user
}
size_t separation( const User *user1, const User *user2 ) {
return;
//queue a DFS
// queue a BFS
//
}
//search using a queue BFS
//search using a DFS
//number of users and their names
void dump_data() {
if (initAmigo->front != NULL) {
node *currNode = initAmigo->front;
printf("%s: Amigos!\n", currNode->data->name); //prints the name of the first node
while ( currNode->next != NULL ) {
currNode = currNode->next;
printf("%s: Amigos!\n", currNode->data->name);
}
//while loop of each user set to currNodw
//set a variable for currNodeAmigo and print the names of them inside ^^^
}
}
void destroy_amigonet(){
//clear Friend Queue and destroy for each User Friend
//destroy initAmigo queue
}
答案 0 :(得分：1)
问题如下：
typedef struct node { void* data; struct node *next; }node; ... struct node *currNode; if (currNode->data->name == name) { //If front is the name being searched return currNode->data; }
currNode->data的类型为void *。这是一个不完整的类型，这意味着它不能被解除引用。编译器不知道它指向的是什么。您需要将转换 void指针转换为指向有意义类型的指针。
您尚未在发布的代码中定义User类型，但我猜您想要这样的内容：
User *user = currNode->data;
if (user->name == name) {
return user;
}
您还必须在同一功能的其他地方进行类似的更改。