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[英]Can you have in C variable length arguments functions with cases when you don't want to pass any variable?
[英]i have been on this question for quaring the document for two days straight, and it is not working. don't want to cheat, can you point the problem
我無法調試正在發生的事情。 代碼似乎是正確的,但我對指針的指針不熟悉,這里有 4 個系列。
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#define MAX_CHARACTERS 1005
#define MAX_PARAGRAPHS 5
char *kth_word_in_mth_sentence_of_nth_paragraph(char ****document, int k, int m, int n) {
return *(*(*(document + n - 1) + m - 1) + k - 1);
}
char **kth_sentence_in_mth_paragraph(char ****document, int k, int m) {
return (*(*(document + m - 1) + k - 1));
}
char ***kth_paragraph(char ****document, int k) {
return *(document + k - 1);
}
char ****get_document(char *text) {
/* allocating memory */
int len = strlen(text);
/* allocate memory for each component first */
char ****document = malloc(sizeof(char ***));
char ***paragraph = malloc(sizeof(char **));
char **sentence = malloc(sizeof(char *));
char *word = malloc(sizeof(char) * 1024);
/* connect all the components to point in the sequence that is required */
*document = paragraph;
*paragraph = sentence;
*sentence = word;
/* declare some numbers as iterators for the words, sentences,etc. */
int parano = 0;
int sentno = 0;
int wordno = 0;
int charno = 0;
/* now iterate over the text filling and expanding the document at the same time */
/*----------------------------------------------------------------------------------------------------*/
/* feeding data in those spaces */
for (int i = 0; i < len; i++) {
if (text[i] == ' ') {
/* wrapping the current word, that is, resizing to len + 1 */
char *current_word = *(*(*(document + parano) + sentno) + wordno);
current_word = realloc(current_word, strlen(current_word) + 1);
/* resizing the current sentence to add another word*/
char **current_sentence = (*(*(document + parano) + sentno));
current_sentence = realloc(current_sentence, sizeof(char *) * (wordno + 2));
wordno++;
charno = 0;
/* allocating space to that new char * / word that has been created in the same sentence */
*(*(*(document + parano) + sentno) + wordno) = malloc(sizeof(char) * 1000);
}
else if (text[i] == '.') {
/* wrapping of the current word has to be done anyways */
char *current_word1 = *(*(*(document + parano) + sentno) + wordno);
current_word1 = realloc(current_word1, strlen(current_word1) + 1);
charno = 0;
if (text[i + 1] != '\n') {
/* the paragraph does not change, and the sentence ends */
/* resize that paragraph for adding another sentence */
char ***current_para = *(document + parano);
current_para = realloc(current_para, sizeof(char **) * (sentno + 2));
sentno++;
wordno = 0;
/* allocating word to that sentence */
*(*(document + parano) + sentno) = malloc(sizeof(char *));
/* allocating space for that word */
*(*(*(document + parano) + sentno) + wordno) = malloc(sizeof(char) * 1000);
} else {
/* if this is the last sentence of this paragraph*/
wordno = 0;
charno = 0;
sentno = 0;
}
}
else if (text[i] == '\n') {
/* paragraph has changed */
/* add another paragraph to the document */
document = realloc(document, sizeof(char ***) * (parano + 2));
parano++;
/* add sentence to that paragraph */
(*(document + parano) ) = malloc(sizeof(char **));
/* add a word to that paragrapgh */
(*(*(document + parano) + sentno)) = malloc(sizeof(char *));
/* allocate space for that word */
*(*(*(document + parano) + sentno) + wordno) = malloc(sizeof(char) * 1000);
} else {
scanf("%c", *(*(*(document + parano) + sentno) + wordno) + charno);
printf("%c\n", **(*(*(document + parano) + sentno) + wordno) + charno);
charno++;
}
}
return document;
}
char *get_input_text() {
int paragraph_count;
scanf("%d", ¶graph_count);
char p[MAX_PARAGRAPHS][MAX_CHARACTERS], doc[MAX_CHARACTERS];
memset(doc, 0, sizeof(doc));
getchar();
for (int i = 0; i < paragraph_count; i++) {
scanf("%[^\n]%*c", p[i]);
strcat(doc, p[i]);
if (i != paragraph_count - 1)
strcat(doc, "\n");
}
char *returnDoc = (char *)malloc((strlen(doc)+1) * (sizeof(char)));
strcpy(returnDoc, doc);
return returnDoc;
}
void print_word(char *word) {
printf("%s", word);
}
void print_sentence(char **sentence) {
int word_count;
scanf("%d", &word_count);
for (int i = 0; i < word_count; i++) {
printf("%s", sentence[i]);
if (i != word_count - 1)
printf(" ");
}
}
void print_paragraph(char ***paragraph) {
int sentence_count;
scanf("%d", &sentence_count);
for (int i = 0; i < sentence_count; i++) {
print_sentence(*(paragraph + i));
printf(".");
}
}
int main() {
char *text = get_input_text();
char ****document = get_document(text);
int q;
scanf("%d", &q);
while (q--) {
int type;
scanf("%d", &type);
if (type == 3) {
int k, m, n;
scanf("%d %d %d", &k, &m, &n);
char *word = kth_word_in_mth_sentence_of_nth_paragraph(document, k, m, n);
print_word(word);
}
else if (type == 2) {
int k, m;
scanf("%d %d", &k, &m);
char **sentence = kth_sentence_in_mth_paragraph(document, k, m);
print_sentence(sentence);
} else {
int k;
scanf("%d", &k);
char ***paragraph = kth_paragraph(document, k);
print_paragraph(paragraph);
}
printf("\n");
}
}
這是 Hackerrank 上針對 C 語言的問題之一。 鏈接到問題hacker rank question my profile
顯示已中止, realloc
無效大小。 在過去的兩天里我找不到任何東西。
問題的輸入
2
Learning C is fun.
Learning pointers is more fun.It is good to have pointers.
3
1 2
2
5
6
2 1 1
4
3 1 1 1
預計 output
Learning pointers is more fun.It is good to have pointers.
Learning C is fun
Learning
text
進行操作,即而不是: scanf("%c", &document[parano][sentno][wordno][charno]);
printf("%c\n", document[parano][sentno][wordno][charno]);
charno++;
你想做:
document[parano][sentno][wordno][charno++] = text[i];
當我們第一次點擊text[i] == ' '
時, ***document
的值是“3\n1 2\n2\n”,但你希望它是“Learning”。
(不固定)當處理一個單詞 (`text[i] == ' ') 時,您擴展了當前單詞,但是,當您最初分配它時,您硬編碼了 1000,所以這沒有意義。 始終如一。
sentno
、 parano
、 wordno
、 charno
是索引,但同樣表明它們是計數。 混淆並沒有錯,為什么在重新定位時必須使用wordno + 2
。
以‘\0’結束單詞。
當你處理 ' ' 時,你添加了另一個你可能需要也可能不需要的詞,這很好。 但是當處理一個'。' 你先看看后面的字母是不是\n
。 始終如一。 如果你向前看,那么你需要檢查i + 1 < len
,它很脆弱,比如說,在\n
之前有一個雜散空間。
(未修復)Memory 泄漏。 由於子元素(段落、句子和單詞)的大小是get_document()
的私有實現細節,您將重構代碼以使其可用。 我建議:
struct document {
char ****document;
size_t paragraphs;
size_t sentences;
size_t words;
}
(不固定)重復數據刪除。 與打印功能類似,為每種類型創建分配 function。
(不固定,真的) get_input_text()
。 您將其拆分為段落,然后將所有內容再次連接到一個局部變量中,然后將其復制到一個動態分配的變量中:
char *str = malloc(BUFFER_LEN);
for(size_t i = 0, l = 0; l < lines && i + 1 < BUFFER_LEN; i += strlen(str + i)) {
int rv = fgets(str + i, BUFFER_LEN - i, stdin);
if(!rv) {
// handle error
break;
}
}
return s;
main(), you read a query type then 1 to 3 numbers.
scanf()` 告訴您讀取了多少項目,因此您只需執行即可。 由於您不將 kth_ 函數用於任何其他用途,因此只需將其與 print_ funci 結合使用 int n = scanf("%d %d %d %d", &type, &p, &s, &w);
switch(type) {
case 1:
if(n != 2) {
// handle error
}
print_paragraph(document, p);
break;
...
}
(未修復)為剩余的malloc()
、 strdup()
等添加錯誤檢查。
不要硬編碼魔法值 (1000)。 我介紹了常量WORD_LEN
,但您也有 MAX_CHARACTERS,這是一回事。
(不固定)考慮使用char *s = strpbrk(text + i, ".\n")
一次復制一個單詞。 它將簡化\0
處理,並且可能比一次一個字節地遍歷text
更快,即i += s - text + i
,只需處理s == NULL
特殊情況。
valgrind 現在很高興除了泄漏(見上文):
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_CHARACTERS 1005
#define MAX_PARAGRAPHS 5
#define WORD_LEN 1000
char *kth_word_in_mth_sentence_of_nth_paragraph(char ****document, int p, int s, int w) {
return document[p - 1][s - 1][w - 1];
}
char **kth_sentence_in_mth_paragraph(char ****document, int p, int s) {
return document[p - 1][s - 1];
}
char ***kth_paragraph(char ****document, int p) {
return document[p - 1];
}
char ****get_document(char* text) {
char ****document = malloc(sizeof ***document);
*document = malloc(sizeof **document);
**document = malloc(sizeof *document);
***document = malloc(WORD_LEN);
/* declare some numbers as iterators for the words, sentences,etc.*/
int parano = 0;
int sentno = 0;
int wordno = 0;
int charno = 0;
/* now iterate over the text filling and expanding the document at the same time*/
/*----------------------------------------------------------------------------------------------------*/
/* feading data in those spaces*/
size_t len = strlen(text);
for (size_t i = 0; i < len; i++) {
switch(text[i]) {
case ' ': {
document[parano][sentno][wordno][charno] = '\0';
wordno++;
char **words = realloc(
document[parano][sentno],
(wordno + 1) * sizeof *document[parano][sentno]
);
if(!words) {
printf("realloc of words failed\n");
exit(1);
}
document[parano][sentno] = words;
document[parano][sentno][wordno] = malloc(WORD_LEN);
charno = 0;
break;
}
case '.': {
document[parano][sentno][wordno][charno] = '\0';
sentno++;
char ***sentences = realloc(
document[parano],
(sentno + 1) * sizeof *document[parano]
);
if(!sentences) {
printf("realloc of sentences failed\n");
exit(1);
}
document[parano] = sentences;
document[parano][sentno] = malloc(sizeof **document);
wordno = 0;
document[parano][sentno][wordno] = malloc(WORD_LEN);
charno = 0;
break;
}
case '\n': {
document[parano][sentno][wordno][charno] = '\0';
parano++;
char ****paragraphs = realloc(
document,
(parano + 1) * sizeof *document
);
if(!paragraphs) {
printf("realloc of paragraphs failed\n");
exit(1);
}
document = paragraphs;
document[parano] = malloc(sizeof ***document);
sentno = 0;
document[parano][sentno] = malloc(sizeof **document);
wordno = 0;
document[parano][sentno][wordno] = malloc(WORD_LEN);
charno = 0;
break;
}
default: // character
document[parano][sentno][wordno][charno++] = text[i];
}
}
return document;
}
char *get_input_text() {
int paragraph_count;
scanf("%d", ¶graph_count);
char p[MAX_PARAGRAPHS][MAX_CHARACTERS];
char doc[MAX_CHARACTERS];
memset(doc, 0, sizeof doc);
getchar();
for (int i = 0; i < paragraph_count; i++) {
scanf("%[^\n]%*c", p[i]);
strcat(doc, p[i]);
if (i != paragraph_count - 1)
strcat(doc, "\n");
}
return strdup(doc);
}
void print_word(char *word) {
printf("%s", word);
}
void print_sentence(char **sentence) {
int word_count;
scanf("%d", &word_count);
for(int i = 0; i < word_count; i++){
print_word(sentence[i]);
if(i + 1 != word_count)
printf(" ");
}
}
void print_paragraph(char ***paragraph) {
int sentence_count;
scanf("%d", &sentence_count);
for (int i = 0; i < sentence_count; i++) {
print_sentence(paragraph[i]);
printf(".");
}
}
int main() {
char *text = get_input_text();
char ****document = get_document(text);
int q;
scanf("%d", &q);
while (q--) {
int type;
scanf("%d", &type);
switch(type) {
case 1: {
int p;
scanf("%d", &p);
print_paragraph(kth_paragraph(document, p));
break;
}
case 2: {
int p, s;
scanf("%d %d", &p, &s);
print_sentence(kth_sentence_in_mth_paragraph(document, p, s));
break;
}
case 3: {
int p, s, w;
scanf("%d %d %d", &p, &s, &w);
print_word(kth_word_in_mth_sentence_of_nth_paragraph(document, p, s, w));
break;
}
default:
printf("error\n");
}
printf("\n");
}
free(text);
}
Output 如預期:
Learning pointers is more fun.It is good to have pointers.
Learning C is fun
Learning
順便說一句,解決這個問題的一種完全不同的方法是保留原始輸入( text
),然后編寫函數直接從該字符串中提取段落、句子或單詞。 如果您輸入的內容很大,則創建一個索引,例如,( paragraph
, sentence
, word
) 到&text[i]
。
終於做到了。 非常感謝@allanwind 的支持
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include<assert.h>
#define MAX_CHARACTERS 1005
#define MAX_PARAGRAPHS 5
char *kth_word_in_mth_sentence_of_nth_paragraph(char ****document, int k, int m, int n) {
return *(*(*(document + n - 1) + m - 1) + k - 1);
}
char **kth_sentence_in_mth_paragraph(char ****document, int k, int m) {
return (*(*(document + m - 1) + k - 1));
}
char ***kth_paragraph(char ****document, int k) {
return *(document + k - 1);
}
char ****get_document(char *a)
{
int len = strlen(a);
char ****document = malloc(sizeof(char ***) * MAX_PARAGRAPHS);
int parano = 0;
char ***paragraph = malloc(sizeof(char **) * MAX_CHARACTERS);
int sentno = 0;
char **sentence = malloc(sizeof( char *) * MAX_CHARACTERS);
int wordno = 0;
char *word = malloc(sizeof(char ) * MAX_CHARACTERS);
int charno = 0;
for (int i = 0; i < len; i++)
{
/* after this way, try to learn switch conditionals*/
if (a[i] == ' ')
{
/* if find a space, that is there are more words within the same sentence*/
/* close the word*/
word[charno] = '\0';
/* add the word to the sentence*/
sentence[wordno] = word;
wordno++;
charno = 0;
/* create another word*/
char *tmp = malloc(sizeof(char) * MAX_CHARACTERS);
/* if the word got space without errors,*/
if (tmp != NULL)
{
word = tmp;
}
}
else if (a[i] == '.')
{
// terminate the word
word[charno] = '\0';
// add word to the sentence
sentence[wordno] = word;
wordno = 0;
charno = 0;
// add sentence to paragraph
paragraph[sentno] = sentence;
if (i != len - 1)
{
sentno++;
// allocate space for new sentence, as it is not the end
char **tmp1 = malloc(sizeof(char *) * MAX_CHARACTERS);
if (tmp1 != NULL)
{
sentence = tmp1;
}
// allocate space for new word
char *tmp2 = malloc(sizeof(char) * MAX_CHARACTERS);
if (tmp2 != NULL)
{
word = tmp2;
}
}
else
{
document[parano] = paragraph;
}
}
else if (a[i] == '\n')
{
// add paragraph to the document
document[parano] = paragraph;
parano++;
// allocate memory for another paragraph
char ***tmp3 = malloc(sizeof(char **) * MAX_CHARACTERS);
if (tmp3 != NULL)
{
paragraph = tmp3;
}
charno = 0;
wordno = 0;
sentno = 0;
}
else
{
/* step 1 read the text into the word char by char*/
word[charno] = a[i];
charno++;
}
}
return document;
}
char* get_input_text() {
int paragraph_count;
scanf("%d", ¶graph_count);
char p[MAX_PARAGRAPHS][MAX_CHARACTERS], doc[MAX_CHARACTERS];
memset(doc, 0, sizeof(doc));
getchar();
for (int i = 0; i < paragraph_count; i++) {
scanf("%[^\n]%*c", p[i]);
strcat(doc, p[i]);
if (i != paragraph_count - 1)
strcat(doc, "\n");
}
char* returnDoc = (char*)malloc((strlen (doc)+1) * (sizeof(char)));
strcpy(returnDoc, doc);
return returnDoc;
}
void print_word(char* word) {
printf("%s", word);
}
void print_sentence(char** sentence) {
int word_count;
scanf("%d", &word_count);
for(int i = 0; i < word_count; i++){
printf("%s", sentence[i]);
if( i != word_count - 1)
printf(" ");
}
}
void print_paragraph(char*** paragraph) {
int sentence_count;
scanf("%d", &sentence_count);
for (int i = 0; i < sentence_count; i++) {
print_sentence(*(paragraph + i));
printf(".");
}
}
int main()
{
char* text = get_input_text();
char**** document = get_document(text);
int q;
scanf("%d", &q);
while (q--) {
int type;
scanf("%d", &type);
if (type == 3){
int k, m, n;
scanf("%d %d %d", &k, &m, &n);
char* word = kth_word_in_mth_sentence_of_nth_paragraph(document, k, m, n);
print_word(word);
}
else if (type == 2){
int k, m;
scanf("%d %d", &k, &m);
char** sentence = kth_sentence_in_mth_paragraph(document, k, m);
print_sentence(sentence);
}
else{
int k;
scanf("%d", &k);
char*** paragraph = kth_paragraph(document, k);
print_paragraph(paragraph);
}
printf("\n");
}
}
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