我是C语言编程的新手，也是我的一个类的作业，我们编写的代码可以在文本文件中读取，将所有单词放在带有计数器的链表中，然后输出该链表进入文本文件。
我不确定我在下面的代码中做错了什么，它只计算一些单词并且似乎跳过其他单词。 （我添加了许多额外的打印件以尝试查看单词丢失的位置）
然后，当我们将所有单词添加到链接列表时，我尝试将所有单词设为小写，但这似乎使它更少读取单词而且我不知道为什么。
非常感谢任何帮助/建议。
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
typedef struct s_words {
char *str; //word
int count; //number of times word occurs
struct s_words* next; //pointer to next word
} words;
words* create_words(char* word) {
//+allocate space for the structure
printf("%lu ", strlen(word));
words* newWord = malloc(sizeof(words));
if (NULL != newWord)
{
//+allocate space for storing the new word in "str"
//+if str was array of fixed size, storage wud be wasted
newWord->str = (char *)malloc((strlen(word))+1);
strcpy(newWord->str, word); //+copy “word” into newWord->str
newWord->str[strlen(word)]='\0';
printf(" Create: %s ", newWord->str);
//+initialize count to 1;
newWord->count = 1;
//+initialize next;
newWord->next = NULL;
}
return newWord;
}
words* add_word(words* wordList, char* word)
{
int found=0;
words *temp=wordList;
//+ search if word exists in the list; if so, make found=1
while (temp != NULL)
{
if (strcmp(temp->str, word) == 0)
{ //+use strcmp command
found=1;
temp->count = temp->count+1; //+increment count;
return wordList;
}
else
{
//+update temp
temp = temp->next;
}
}
if (found==0)
{ //new word
//printf("%s ", word);
words* newWord = create_words(word);
if (NULL != newWord)
{
//+?? Insert new word at the head of the list
newWord->next = wordList;
printf(" NEW WORD: %s\n ", newWord->str);
}
return newWord;
}
//return wordList; //code never gets here, just added in case of error
}
int main(int argc, char* argv[])
{
words *mywords; //+head of linked list containing words
mywords=NULL;
FILE *myFile;
FILE *myOutput;
char* filename = argv[1];
char* outputfile = argv[2];
myFile = fopen(filename, "r"); //+first parameter is input file
if (myFile==0)
{
printf("file not opened\n");
return 1;
}
else
{
printf("file opened \n");
}
//+start reading file character by character;
//+when word has been detected; call the add_word function
int ch = 0, word = 1, k = 0;
char thisword[100];
//ch = putchar(tolower(ch));
//ch = fgetc(myFile);
while ((ch = fgetc(myFile)) != EOF )
{
//error handling
if (ch == '.' || ch == ' ' || ch == ',' || ch == ':' || ch == ';' || ch == '\n') //+detect new word? Check if ch is a delimiter
{ //when above if is true, new word created in next if:
if ( word == 1 ) //+make sure previous character was not delimiter
{
word = 0;
//+make the kth character of thisword as \0
thisword[k] = '\0';
//+now call add_word to add thisword into the list
printf(" Add:%s ", thisword);
mywords = add_word(mywords, thisword);
printf(" Added:%s\n", mywords->str);
k=0;
}
}
else
{
word = 1;
//make ch lowercase
//ch = putchar(toupper(ch));
//+?? //make the kth character of thisword equal to ch
thisword[k] = ch;
thisword[k] = putchar(tolower(thisword[k]));
k++;
}
}
if (word == 1)
{
thisword[k] = '\0';
//add thisword into the list
printf("Last Word:%s ", thisword);
mywords = add_word(mywords, thisword);
}
words *currword;
printf("printing list\n");
//+Traverse list and print each word and its count to outputfile
//+output file is second parameter being passed
myOutput = fopen(outputfile, "w+"); //+first parameter is input file
if (myOutput == 0)
{
printf("output file not opened \n");
return 1;
}
else
{
printf("output file opened \n");
}
currword = mywords;
while (currword->next != NULL)
{
//add word name then word count to file, then move to next
fprintf(myOutput, "%s %d \n", currword->str, currword->count);
printf("%s ", currword->str);
currword = currword->next;
}
return 0;
}
答案 0 :(得分：0)
你肯定喜欢自己努力...你的四大问题是（1）没有将 mywords的地址传递给{{1 }}，（2）无法处理add_words中的新/空列表案例，（3）将新节点添加到列表的头部，每次拨打add_words时，（4）都会覆盖您的列表地址（例如add_word）
修复每个问题并整理解析，您应该能够在列表中找到所有单词。查看/测试以下内容：
mywords = add_words...输入文件
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
typedef struct s_words {
char *str; //word
int count; //number of times word occurs
struct s_words *next; //pointer to next word
} words;
words *create_words (char *word)
{
//+allocate space for the structure
printf ("%lu ", strlen (word));
words *newWord = malloc (sizeof (words));
if (NULL != newWord) {
//+allocate space for storing the new word in "str"
//+if str was array of fixed size, storage wud be wasted
newWord->str = (char *) malloc ((strlen (word)) + 1);
strcpy (newWord->str, word); //+copy “word” into newWord->str
newWord->str[strlen (word)] = '\0';
printf (" Create: %s ", newWord->str);
//+initialize count to 1;
newWord->count = 1;
//+initialize next;
newWord->next = NULL;
}
return newWord;
}
words *add_word (words **wordList, char *word)
{
if (!*wordList) { /* handle EMPTY list */
printf ("NEW LIST\n");
return *wordList = create_words (word);
}
words *temp = *wordList;
//+ search if word exists in the list; if so, make found=1
while (temp->next != NULL) { /* iterate while temp->next != NULL */
if (strcmp (temp->str, word) == 0) { //+use strcmp command
temp->count = temp->count + 1; //+increment count;
return *wordList;
}
else
temp = temp->next; //+update temp
}
words *newWord = create_words (word);
if (NULL != newWord) { /* insert at TAIL of list */
temp->next = newWord;
printf (" NEW WORD: %s\n ", newWord->str);
}
return newWord;
}
int main (int argc, char *argv[]) {
words *mywords; //+head of linked list containing words
mywords = NULL;
char *delim = ". ,:;\t\n";
FILE *myFile;
FILE *myOutput;
char *filename = argv[1];
char *outputfile = argv[2];
if (argc != 3) {
fprintf (stderr, "error: insufficient input. usage: %s ifile ofile\n",
argv[0]);
return 1;
}
myFile = fopen (filename, "r"); //+first parameter is input file
if (myFile == 0) {
printf ("file not opened\n");
return 1;
} else {
printf ("file opened \n");
}
//+start reading file character by character;
//+when word has been detected; call the add_word function
int ch = 0, word = 1, k = 0;
char thisword[100];
while ((ch = fgetc (myFile)) != EOF) { /* for each char */
if (strchr (delim, ch)) { /* check if delim */
if (word == 1) { /* if so, terminate word, reset */
word = 0;
thisword[k] = '\0';
printf ("\nadd_word (mywords, %s)\n", thisword);
/* do NOT overwrite list address each time,
* you must send ADDRESS of list to add_word
* to handle EMPTY list case.
*/
if (add_word (&mywords, thisword))
printf (" added: %s\n", mywords->str);
else
fprintf (stderr, "error: add_word failed.\n");
k = 0;
}
}
else { /* if not delim, add char to string, set word 1 */
word = 1;
thisword[k++] = tolower (ch); /* make ch lowercase */
}
}
if (word == 1) { /* handle non-POSIX line-end */
thisword[k] = '\0';
//add thisword into the list
printf ("\nadd_word (mywords, %s) (last)\n", thisword);
if (add_word (&mywords, thisword)) /* same comment as above */
printf (" added: %s\n", mywords->str);
else
fprintf (stderr, "error: add_word failed.\n");
}
words *currword;
printf ("printing list\n");
//+Traverse list and print each word and its count to outputfile
//+output file is second parameter being passed
myOutput = fopen (outputfile, "w+"); //+first parameter is input file
if (myOutput == 0) {
printf ("output file not opened \n");
return 1;
} else {
printf ("output file opened \n");
}
currword = mywords;
while (currword != NULL) { /* just test currword here */
//add word name then word count to file, then move to next
fprintf (myOutput, "%s %d \n", currword->str, currword->count);
printf ("%s ", currword->str);
currword = currword->next;
}
putchar ('\n');
return 0;
}
测试使用
$ cat ../dat/captnjack.txt
This is a tale
Of Captain Jack Sparrow
A Pirate So Brave
On the Seven Seas.
输出文件
$ ./bin/llwordcount ../dat/captnjack.txt dat/llout.txt
注意：用于打印/输出，您只需要$ cat dat/llout.txt
this 1
is 1
a 2
tale 1
of 1
captain 1
jack 1
sparrow 1
pirate 1
so 1
brave 1
on 1
the 1
seven 1
seas 1
遍历列表。
现在说，您应该考虑使用面向行的输入（while (currword != NULL)或fgets）并将每行数据解析为单词而不是读取逐个字符并寻找分隔符。读取/解析一次一行更容易且更不容易出错。由于面向行的输入是缓冲的，因此读取速度也快得多。你可以一次阅读一个角色，它只是速度较慢，而且还有很多陷阱。
消化更改（上面用getline评论）并告诉我您是否有任何问题。