c语言怎么统计单词出现的次数

在C语言中，可以使用哈希表或者数组来统计单词出现的次数。

1. 使用哈希表：

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

// 定义哈希表的大小
#define HASH_SIZE 100

// 哈希表节点结构
typedef struct Node {
    char word[256];  // 单词
    int count;       // 出现次数
    struct Node* next;
} Node;

// 哈希函数
int hash(char* word) {
    int sum = 0;
    for (int i = 0; i < strlen(word); i++) {
        sum += word[i];
    }
    return sum % HASH_SIZE;
}

// 向哈希表中插入节点
void insert(Node** hashTable, char* word) {
    int index = hash(word);
    Node* newNode = (Node*)malloc(sizeof(Node));
    strcpy(newNode->word, word);
    newNode->count = 1;
    newNode->next = NULL;

    if (hashTable[index] == NULL) {
        hashTable[index] = newNode;
    } else {
        Node* cur = hashTable[index];
        while (cur->next != NULL) {
            if (strcmp(cur->word, word) == 0) {
                cur->count++;
                free(newNode);
                return;
            }
            cur = cur->next;
        }
        if (strcmp(cur->word, word) == 0) {
            cur->count++;
            free(newNode);
        } else {
            cur->next = newNode;
        }
    }
}

// 统计单词出现的次数
void wordCount(char* sentence) {
    Node* hashTable[HASH_SIZE] = {NULL};

    char* word = strtok(sentence, " ");
    while (word != NULL) {
        insert(hashTable, word);
        word = strtok(NULL, " ");
    }

    for (int i = 0; i < HASH_SIZE; i++) {
        Node* cur = hashTable[i];
        while (cur != NULL) {
            printf("%s: %d\n", cur->word, cur->count);
            cur = cur->next;
        }
    }
}

int main() {
    char sentence[] = "this is a test sentence to count word occurrences";
    wordCount(sentence);
    return 0;
}

2. 使用数组：

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

// 统计单词出现的次数
void wordCount(char* sentence) {
    typedef struct {
        char word[256];
        int count;
    } Word;
    
    int wordCount = 0;
    Word* wordArray = (Word*)malloc(sizeof(Word) * wordCount);

    char* word = strtok(sentence, " ");
    while (word != NULL) {
        int exist = 0;
        for (int i = 0; i < wordCount; i++) {
            if (strcmp(wordArray[i].word, word) == 0) {
                wordArray[i].count++;
                exist = 1;
                break;
            }
        }
        if (!exist) {
            wordCount++;
            wordArray = (Word*)realloc(wordArray, sizeof(Word) * wordCount);
            strcpy(wordArray[wordCount - 1].word, word);
            wordArray[wordCount - 1].count = 1;
        }
        word = strtok(NULL, " ");
    }

    for (int i = 0; i < wordCount; i++) {
        printf("%s: %d\n", wordArray[i].word, wordArray[i].count);
    }

    free(wordArray);
}

int main() {
    char sentence[] = "this is a test sentence to count word occurrences";
    wordCount(sentence);
    return 0;
}

以上是两种统计单词出现次数的方法，分别使用哈希表和数组来实现。可以根据实际情况选择适合的方法。