从文本文件中读取单词并按字母升序显示所有单词的程序 - C 编程语言

在 C 编程语言中，我们可以通过文件流来读取文本文件中的内容，并对单词进行处理。

#include <stdio.h>
#include <ctype.h>
#include <string.h>

#define MAX_WORD_LEN 100

int main(void) {
    char word[MAX_WORD_LEN];
    char *filename = "text.txt";
    FILE *fp = fopen(filename, "r");

    if (fp == NULL) {
        printf("Failed to open file %s.\n", filename);
        return 1;
    }

    while (fscanf(fp, "%s", word) != EOF) {
        int len = strlen(word);
        if (!isalpha(word[len - 1])) {
            word[len - 1] = '\0';
        }

        printf("%s\n", word);
    }

    fclose(fp);

    return 0;
}

上面的代码片段可以读取文本文件中的每个单词，并在控制台上显示出来。

但是，我们要按字母升序显示所有单词，可以使用数组或链表来存储单词，并对其进行排序。

下面是使用数组来存储单词并按字母升序排序的代码：

#include <stdio.h>
#include <ctype.h>
#include <string.h>

#define MAX_WORD_LEN 100
#define MAX_WORDS 1000

void sort_words(char *words[], int n) {
    for (int i = 0; i < n - 1; i++) {
        for (int j = i + 1; j < n; j++) {
            if (strcmp(words[i], words[j]) > 0) {
                char *tmp = words[i];
                words[i] = words[j];
                words[j] = tmp;
            }
        }
    }
}

int main(void) {
    char word[MAX_WORD_LEN];
    char *filename = "text.txt";
    FILE *fp = fopen(filename, "r");

    if (fp == NULL) {
        printf("Failed to open file %s.\n", filename);
        return 1;
    }

    char *words[MAX_WORDS];
    int n = 0;

    while (fscanf(fp, "%s", word) != EOF) {
        int len = strlen(word);
        if (!isalpha(word[len - 1])) {
            word[len - 1] = '\0';
        }

        int found = 0;
        for (int i = 0; i < n; i++) {
            if (strcmp(words[i], word) == 0) {
                found = 1;
                break;
            }
        }

        if (!found) {
            words[n++] = strdup(word);
        }
    }

    sort_words(words, n);

    for (int i = 0; i < n; i++) {
        printf("%s\n", words[i]);
        free(words[i]);
    }

    fclose(fp);

    return 0;
}

上面的代码片段将单词存储在一个数组中，并使用冒泡排序算法对其进行排序。注意，在排序之前，需要先去除重复的单词。

也可以使用链表来存储单词，并对其进行排序。下面是使用链表来存储单词并按字母升序排序的代码：

#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <stdlib.h>

#define MAX_WORD_LEN 100

typedef struct node {
    char word[MAX_WORD_LEN];
    struct node *next;
} Node;

Node *create_node(char *word) {
    Node *node = malloc(sizeof(Node));
    strcpy(node->word, word);
    node->next = NULL;
    return node;
}

void free_list(Node *head) {
    while (head != NULL) {
        Node *tmp = head;
        head = head->next;
        free(tmp);
    }
}

void insert_node(Node **head, char *word) {
    Node *prev = NULL;
    Node *curr = *head;
    Node *node = create_node(word);

    while (curr != NULL && strcmp(curr->word, word) < 0) {
        prev = curr;
        curr = curr->next;
    }

    if (prev == NULL) {
        node->next = *head;
        *head = node;
    } else {
        node->next = curr;
        prev->next = node;
    }
}

int main(void) {
    char word[MAX_WORD_LEN];
    char *filename = "text.txt";
    FILE *fp = fopen(filename, "r");

    if (fp == NULL) {
        printf("Failed to open file %s.\n", filename);
        return 1;
    }

    Node *head = NULL;

    while (fscanf(fp, "%s", word) != EOF) {
        int len = strlen(word);
        if (!isalpha(word[len - 1])) {
            word[len - 1] = '\0';
        }

        int found = 0;
        Node *prev = NULL;
        Node *curr = head;
        while (curr != NULL) {
            int cmp = strcmp(curr->word, word);
            if (cmp == 0) {
                found = 1;
                break;
            } else if (cmp > 0) {
                break;
            } else {
                prev = curr;
                curr = curr->next;
            }
        }

        if (!found) {
            insert_node(&head, word);
        }
    }

    Node *curr = head;
    while (curr != NULL) {
        printf("%s\n", curr->word);
        curr = curr->next;
    }

    free_list(head);
    fclose(fp);

    return 0;
}

上面的代码片段使用一个链表来存储单词，并在插入时保持其按字母升序排序。注意，在插入之前，需要先去除重复的单词。