我创造了，我认为是一个双重链接列表。我们的想法是反转在新行上输入的单词的输出，所以：
Hello\nAll\n.
.\nAll\nHello
想法是遍历我的列表，直到找到'\n'，然后向相反的方向打印，然后返回到我离开的地方，继续遍历直到另一条新线，然后再前进并打印等
然而，我目前的实施似乎无法开始工作而且我已经碰到了一堵砖墙，并且提示或提示受到赞赏！
typedef struct L {
char val;
struct L *next;
struct L *prev;
}List;
List *insertList(char val, List *t1 );
List *createList(void);
int main(void) {
List *z = createList();
List *pos = z;
while (pos != NULL) {
while ( z->val != '\n' ) {
if (z == NULL)
break;
z = z->next;
pos = z;
}
while (z != NULL) {
printf("%c", z->val);
z = z->prev;
}
}
return 0;
}
List *createList(void) {
List *h = NULL;
char c;
do {
c =(char)getchar();
h = insertList(c, h);
}while(c != '.');
return h;
}
List *insertList( char val, List *t1) {
List *t = calloc(1, sizeof( List ));
t->prev = NULL;
t->val = val;
t->next = t1;
if (t1 != NULL) {
t1->prev = t;
}
return t;
}
答案 0 :(得分：1)
尝试使用while while循环[编辑注意Chris关于检查LL结尾的评论]：
while (pos != NULL) {
while (z != NULL) {
// if you've reached the line feed or the end of the linked list
if ((z->val == '\n') || (z->next == NULL)) {
pos = z->next; // store list position just after this char for next time through
break;
}
z = z->next;
}
while (z != NULL) {
printf("%c", z->val);
z = z->prev;
// don't print more than just this word!:
if ((z != NULL) && (z->val == '\n'))
break;
}
// reset z for top inner while loop
z = pos;
}
基本问题是当外部while循环缠绕时z未被重置;第二个问题是链表的结尾没有突破第一个内部while循环;第三个问题是第二个内部，而循环没有检查它正在打印的单词的结尾。
您还需要在结尾处释放链接列表，否则将导致内存泄漏。您还应该检查calloc()的返回值，以确保它不返回null。
答案 1 :(得分：1)
我认为您的结构需要更改，并且没有理由使用双链表来解决您的问题。
你的结构应该包含
struct node {
char *word;
struct node *next;
};
然后你的主循环应该是这样的：
1) Read character data until delimiter into expandable buffer. Add NULL string terminator.
2) When delimiter is reached create node that points to buffer.
3) Insert NODE at HEAD of list.
4) When '.' is reached print each string starting from head of list.
答案 2 :(得分：0)
好的，我有时间看看为什么我的第一个答案不起作用 - 如果您通过调试器运行代码，那么一些显而易见的事情。所以这是一个完全正常的版本。它可能会进行相当多的优化，但它遵循与原始代码相同的结构，所以希望您可以遵循它：
typedef struct L {
char val;
struct L *next;
struct L *prev;
} List;
List* insertList( char val, List *t1 ) {
List *t = calloc(1, sizeof( List ));
t->prev = NULL;
t->val = val;
t->next = t1;
if (t1 != NULL)
t1->prev = t;
return t;
}
List* createList( void ) {
List *h = NULL;
char c;
do {
c =(char)getchar();
h = insertList( c, h );
} while (c != '.');
return h;
}
void freeList( List *list ) {
// free the linked list
if (list != NULL) {
freeList( list->next );
free( list );
}
}
int main( void ) {
// create list
List *head = createList();
List *pos = head, *currentChar = NULL, *wordStart = NULL;
while (pos != NULL)
{
// find next word
wordStart = NULL;
while (pos != NULL)
{
// gone past the beginning of a word yet?
if ((pos->val == '\n') || (pos->next == NULL))
{
wordStart = (pos->next == NULL) ? pos : pos->prev; // note where this word starts
pos = pos->next; // jump over \n, or go to end of list (null), for next time into this loop
break; // jump out of this loop so we can output the word
}
else // not found end of word yet - on to next char
pos = pos->next;
}
// have we found a word? if so, output it!
if (wordStart != NULL)
{
currentChar = wordStart; // start at first char in the word
while (currentChar != NULL)
{
printf( "%c", currentChar->val ); // output this char
currentChar = currentChar->prev; // on to next char in the word
if ((currentChar != NULL) && (currentChar->val == '\n'))
break; // stop after last char of the word
}
// print the line-feed just before wordStart (if there is one)
if (wordStart->next != NULL)
printf( "%c", wordStart->next->val );
}
else // we've reached the end - stop
break; // not really necessary - pos should be NULL at this point anyway
}
freeList( head ); // free linked list memory
return 0;
}
主要变化是我如何输出换行符。我意识到这不是你需要的每个单词之后的换行符，而是它之前的那个单词（完全没有逻辑 - 我想知道这个问题原来是什么意思？）。但它现在输出你所需要的。我已经添加了一个函数来为你释放链表内存。 ：）
答案 3 :(得分：0)
#include<stdio.h>
#include<conio.h>
#include<malloc.c>
struct dnode{
int data;
struct dnode *prev,*next;
};
typedef struct dnode DNODE;
DNODE *first;
DNODE *last;
DNODE* createDnode(int ele){
DNODE *nnode;
nnode=(DNODE *)malloc(sizeof(DNODE));
nnode->data=ele;
nnode->next=NULL;
nnode->prev=NULL;
return nnode;
}
//Insert First
DNODE *insertFirst(int ele){
DNODE *nnode;
nnode=createDnode(ele);
if(first==NULL){ //if node is creating first time
first=last=nnode;
return;
}
nnode->prev=NULL;
nnode->next=first;
first=nnode;
return first;
}
//Insert Last
DNODE *insertLast(int ele){
DNODE *nnode;
nnode=createDnode(ele);
if(first==NULL){ //if node is creating first time
first=last=nnode;
return;
}
last->next=nnode;
nnode->prev=last;
last=nnode;
return last;
}
//Insert Before an Element
DNODE *insertBefore(int ele,int key){
DNODE *nnode,*curr,*pre;
nnode=createDnode(ele);
if(first==NULL){ //if node is creating first time
first=last=nnode;
return;
}
if(first->data==key){ // if key is found at first node
nnode->next=first;
first=nnode;
return first;
}
curr=first;
while(curr && curr->data!=key){
pre=curr;
curr=curr->next;
}
if(!curr){ //if search not found then curr will be NULL, it's means the node is added at last
last->next=nnode;
nnode->prev=last;
last=nnode;
return last;
}
curr->prev->next=nnode;
nnode->prev=curr->prev;
nnode->next=curr;
curr->prev=nnode;
return;
}
// Insert After an Element
DNODE *insertAfter(int ele,int key){
DNODE *nnode,*curr,*pre;
nnode=createDnode(ele);
if(first==NULL){ //if node is creating first time
first=last=nnode;
return;
}
curr=first;
while(curr && curr->data!=key){
//pre=curr;
curr=curr->next;
}
if(!curr){ //if search not found then curr will be NULL, it's means the node is added at last
last->next=nnode;
nnode->prev=last;
last=nnode;
return last;
}
nnode->next=curr->next;
curr->next->prev=nnode;
nnode->prev=curr;
curr->next=nnode;
return;
}
//删除功能
int removeNode(int key){
DNODE *curr;
if(first==NULL){ //if node is creating first time
printf("\n\nList is Empty");
return -1;
}
curr=first;
if(first->data==key){ //if first node has key
first=first->next;
first->prev=NULL;
curr->next = NULL;
free(curr);
return;
}
while(curr && curr->data!=key){
curr=curr->next;
}
if(!curr){ //if search not found then curr will be NULL,
return -1;
}
curr->prev->next=curr->next;
curr->next->prev=curr->prev;
curr->next = curr->prev = NULL;
printf("\n\n%d is Successfully Deleted: ",curr->data);
free(curr);
return;
}
void display(){
DNODE *curr;
if(first==NULL)
printf("\n\nNothing to Display\n\n");
curr=first;
printf("\n\n\tElement in List\n\n\t");
while(curr){
printf("%d ",curr->data);
curr=curr->next;
}
}
main(){
int ele,ch,key;
do{
printf("\nEnter Your Choice: \n");
printf("1-Insert First\t2-Insert Last\n3-Insert Before\t4-Insert After\n5-Remove \t6-Display\n");
scanf("%d",&ch);
switch(ch){
case 1:
printf("Enter Element To Insert: ");
scanf("%d",&ele);
insertFirst(ele);
break;
case 2:
printf("Enter Element To Insert: ");
scanf("%d",&ele);
insertLast(ele);
break;
case 3:
printf("Enter Element To Insert: ");
scanf("%d",&ele);
printf("\nEnter Key: ");
scanf("%d",&key);
insertBefore(ele,key);
break;
case 4:
printf("Enter Element To Insert: ");
scanf("%d",&ele);
printf("\nEnter Key: ");
scanf("%d",&key);
insertAfter(ele,key);
break;
case 5:
printf("Enter Key to Delete: ");
fflush(stdin);
scanf("%d",&key);
removeNode(key);
break;
case 6:
display();
break;
}
}while(ch!=7);
getch();
return 0;
}