此代码与您的代码非常相似，但解决了一个稍微不同的问题，因为它接受任意文本文件并不管其中的字符如何都对其进行处理。它以英语使用者的典型风格将重音字符视为“非字母”（部分原因是它不使用setlocale()，部分原因是它不处理多字节或宽字符）。它计算每个单词出现的次数（在 64 位机器上不占用数据结构中的额外空间）。当然，它包括一个打印功能，这对于检查它是否正确地完成了工作很重要。
#include <ctype.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct node
{
bool wordBool;
int wordCount;
struct node *next[27]; // 26 letters and one space for the apostrophe
} node;
static const char trie_map[] = "'abcdefghijklmnopqrstuvwxyz";
static node *base = 0;
static int numWords = 0;
static void oom(void)
{
fprintf(stderr, "Out of memory\n");
exit(EXIT_FAILURE);
}
static int trie_index(char c)
{
char *p = strchr(trie_map, tolower(c));
if (p == 0)
return -1;
else
return (p - trie_map);
}
static
bool load(const char *dictionary)
{
FILE *dictionaryf = fopen(dictionary, "r"); // the file to read
if (dictionaryf == 0)
return false;
base = calloc(sizeof(node), 1);
node *currNode = base;
int n;
while ((n = fgetc(dictionaryf)) != EOF)
{
n = trie_index(n);
if (n >= 0)
{
if (currNode->next[n] == NULL)
{
currNode->next[n] = calloc(sizeof(node), 1);
if (currNode->next[n] == NULL)
oom();
}
currNode = currNode->next[n];
}
else if (currNode != base)
{
if (!currNode->wordBool)
{
currNode->wordBool = true;
numWords++;
}
currNode->wordCount++;
currNode = base;
}
/* else: consecutive non-letters, non-apostrophes */
}
if (currNode != base && !currNode->wordBool)
{
currNode->wordBool = true;
numWords++;
}
printf("%i distinct words\n", numWords);
fclose(dictionaryf);
return true;
}
static void print_trie(node *trie, char *buffer, size_t buflen)
{
if (trie != 0)
{
if (trie->wordBool)
printf("Word: %3d [%s]\n", trie->wordCount, buffer);
size_t len = strlen(buffer);
if (len >= buflen - 2)
{
fprintf(stderr, "Word too long!\n[%s]\n", buffer);
exit(EXIT_FAILURE);
}
for (int i = 0; i < 27; i++)
{
if (trie->next[i] != 0)
{
buffer[len] = trie_map[i];
buffer[len+1] = '\0';
print_trie(trie->next[i], buffer, buflen);
}
}
}
}
int main(int argc, char **argv)
{
const char *data = "data";
if (argc == 2)
data = argv[1];
if (load(data))
{
printf("Loaded file '%s' OK\n", data);
char buffer[256] = "";
print_trie(base, buffer, sizeof(buffer));
}
else
printf("Load failed!\n");
return 0;
}
当在自己的源代码 (trie-31.c) 上运行时，它会产生：
94 distinct words
Loaded file 'trie-31.c' OK
Word: 3 [']
Word: 1 ['abcdefghijklmnopqrstuvwxyz]
Word: 1 [and]
Word: 1 [apostrophe]
Word: 1 [apostrophes]
Word: 2 [argc]
Word: 2 [argv]
Word: 7 [base]
Word: 2 [bool]
Word: 10 [buffer]
Word: 3 [buflen]
Word: 2 [c]
Word: 2 [calloc]
Word: 8 [char]
Word: 1 [consecutive]
Word: 3 [const]
Word: 1 [ctype]
Word: 14 [currnode]
Word: 1 [d]
Word: 5 [data]
Word: 2 [dictionary]
Word: 4 [dictionaryf]
Word: 1 [distinct]
Word: 4 [else]
Word: 1 [eof]
Word: 4 [exit]
Word: 1 [failed]
Word: 2 [failure]
Word: 1 [false]
Word: 1 [fclose]
Word: 1 [fgetc]
Word: 3 [file]
Word: 1 [fopen]
Word: 2 [for]
Word: 2 [fprintf]
Word: 5 [h]
Word: 7 [i]
Word: 14 [if]
Word: 5 [include]
Word: 2 [index]
Word: 7 [int]
Word: 4 [len]
Word: 2 [letters]
Word: 3 [load]
Word: 1 [loaded]
Word: 1 [long]
Word: 1 [main]
Word: 4 [map]
Word: 1 [memory]
Word: 16 [n]
Word: 7 [next]
Word: 8 [node]
Word: 2 [non]
Word: 2 [null]
Word: 4 [numwords]
Word: 1 [of]
Word: 1 [ok]
Word: 1 [one]
Word: 2 [oom]
Word: 1 [out]
Word: 3 [p]
Word: 3 [print]
Word: 4 [printf]
Word: 1 [r]
Word: 1 [read]
Word: 5 [return]
Word: 2 [s]
Word: 1 [s']
Word: 2 [size]
Word: 3 [sizeof]
Word: 1 [space]
Word: 7 [static]
Word: 1 [stdbool]
Word: 2 [stderr]
Word: 1 [stdio]
Word: 1 [stdlib]
Word: 1 [strchr]
Word: 1 [string]
Word: 1 [strlen]
Word: 2 [struct]
Word: 2 [t]
Word: 2 [the]
Word: 1 [to]
Word: 1 [tolower]
Word: 1 [too]
Word: 15 [trie]
Word: 3 [true]
Word: 1 [typedef]
Word: 3 [void]
Word: 1 [while]
Word: 2 [word]
Word: 6 [wordbool]
Word: 3 [wordcount]
Word: 1 [words]
有些词包括撇号（有 ' 本身，'abcdefghijklmnopqrstuvwxyz 和 s'）。对于文件great.panjandrum，其中包含：
So she went into the garden
to cut a cabbage-leaf
to make an apple-pie
and at the same time
a great she-bear coming down the street
pops its head into the shop
What no soap
So he died
and she very imprudently married the Barber
and there were present
the Picninnies
and the Joblillies
and the Garyulies
and the great Panjandrum himself
with the little round button at top
and they all fell to playing the game of catch-as-catch-can
till the gunpowder ran out at the heels of their boots
输出是：
66 distinct words
Loaded file 'great.panjandrum' OK
Word: 2 [a]
Word: 1 [all]
Word: 1 [an]
Word: 7 [and]
Word: 1 [apple]
Word: 1 [as]
Word: 3 [at]
Word: 1 [barber]
Word: 1 [bear]
Word: 1 [boots]
Word: 1 [button]
Word: 1 [cabbage]
Word: 1 [can]
Word: 2 [catch]
Word: 1 [coming]
Word: 1 [cut]
Word: 1 [died]
Word: 1 [down]
Word: 1 [fell]
Word: 1 [game]
Word: 1 [garden]
Word: 1 [garyulies]
Word: 2 [great]
Word: 1 [gunpowder]
Word: 1 [he]
Word: 1 [head]
Word: 1 [heels]
Word: 1 [himself]
Word: 1 [imprudently]
Word: 2 [into]
Word: 1 [its]
Word: 1 [joblillies]
Word: 1 [leaf]
Word: 1 [little]
Word: 1 [make]
Word: 1 [married]
Word: 1 [no]
Word: 2 [of]
Word: 1 [out]
Word: 1 [panjandrum]
Word: 1 [picninnies]
Word: 1 [pie]
Word: 1 [playing]
Word: 1 [pops]
Word: 1 [present]
Word: 1 [ran]
Word: 1 [round]
Word: 1 [same]
Word: 3 [she]
Word: 1 [shop]
Word: 2 [so]
Word: 1 [soap]
Word: 1 [street]
Word: 13 [the]
Word: 1 [their]
Word: 1 [there]
Word: 1 [they]
Word: 1 [till]
Word: 1 [time]
Word: 3 [to]
Word: 1 [top]
Word: 1 [very]
Word: 1 [went]
Word: 1 [were]
Word: 1 [what]
Word: 1 [with]