欢迎大家。我是 Stackoverflow 的新手,我用 C 编写了一段时间。 我在编写计算文本文件中单词出现次数的程序时遇到了问题。我需要一个输出来告诉哪个单词出现了多少次。这是源代码:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int new_words=0;
int nwords=0;
typedef struct element{
char word[30];
int how_many;
} element;
int is_word_new(element ** dictionary, char * string)
{
for (int i =0; i<new_words; i++)
{
if (strcmp(string, dictionary[i]->word)==0)
return 0;
}
return 1;
}
int which_word(element ** dictionary, char * string)
{
for (int i =0; i<new_words; i++)
{
if (strcmp(string, dictionary[i]->word)==0)
return i;
}
return 0;
}
int main()
{
FILE * fp;
char word[30];
fp=fopen("input.txt", "r");
if (fp==NULL)
{
printf("FILE ERROR");
return 0;
}
while(!feof(fp))
{
fscanf(fp, "%s",word);
nwords++;
}
nwords--;
rewind(fp);
struct element * dictionary = (element*)malloc(sizeof(element)*nwords);
for (int i =0; i<nwords; i ++)
{
fscanf(fp, "%s", word);
if( is_word_new(&dictionary, word) )
{
strcpy(dictionary[new_words].word, word);
//dictionary[new_words].word= word;
dictionary[new_words].how_many=1;
new_words++;
}
else
dictionary[which_word(&dictionary, word)].how_many++;
word[0]='\0';
}
printf("\n\nFinal dictionary\n with %d words", new_words);
for (int i =0; i<new_words; i++)
{
printf("%s %d \n", dictionary[i].word, dictionary[i].how_many);
}
free(dictionary);
fclose(fp);
return 0;
}
这个想法是,我首先计算文本中有多少个单词(不知何故总是比实际值大一)。函数 is_word_new 检查新读取的单词是否已在字典中。 which_word()
告诉找到哪个单词
但是,我在运行该程序时遇到段错误。
当我使用注释为 //dictionary[i].word=word
的行时,程序的行为就好像字典中只有“word”一样。
请给我提示我哪里做错了
最佳答案
必读问题:Why is “while ( !feof (file) )” always wrong?感谢 Jonathan Leffler 的评论。
<小时/>请检查下面代码中我的评论。当这些词出现一次时,我给你一个启动。我把剩下的工作交给你,这样我们就可以分享乐趣,但你当然可以提出要求。
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int new_words = 0;
int nwords = 0;
typedef struct element {
char word[30];
int how_many;
} element;
// no need to pass double pointer
int is_word_new(element* dictionary, char * string) {
int i;
for (i = 0; i < new_words; i++) {
printf("|%s|, |%s|\n", string, dictionary[i].word);
if (strcmp(string, dictionary[i].word) == 0)
return 0;
printf("i=%d\n",i);
}
return 1;
}
int which_word(element ** dictionary, char * string) {
int i;
for (i = 0; i < new_words; i++) {
if (strcmp(string, dictionary[i]->word) == 0)
return i;
}
return 0;
}
int main() {
FILE * fp;
char word[30];
fp = fopen("test.txt", "r");
if (fp == NULL) {
printf("FILE ERROR");
return 0;
}
printf("file read\n");
int read_counter;
while (!feof(fp)) {
read_counter = fscanf(fp, "%s", word);
// increment only if we really read something
if(read_counter >= 0)
nwords++;
}
// this is wrong, remove it
//nwords--;
rewind(fp);
printf("nwords = %d\n", nwords);
// do not cast what malloc returns. Also struct is not needed.
element * dictionary = malloc(sizeof (element) * nwords);
int i;
for (i = 0; i < nwords; i++) {
fscanf(fp, "%s", word);
printf("read |%s|\n", word);
if (is_word_new(dictionary, word)) {
strcpy(dictionary[new_words].word, word);
//dictionary[new_words].word= word;
dictionary[new_words].how_many = 1;
new_words++;
} else {
printf("bhka\n");
dictionary[which_word(&dictionary, word)].how_many++;
}
//word[0] = '\0';
}
printf("\n\nFinal dictionary\n with %d words", new_words);
for (i = 0; i < new_words; i++) {
printf("%s %d \n", dictionary[i].word, dictionary[i].how_many);
}
free(dictionary);
fclose(fp);
return 0;
}
这是我使用的 test.txt:
sam klouvi george dit epfl
ok
end
关于计算文件 C 中单词的出现次数,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/30808565/