如何在C语言中按字母顺序对文件行进行排序

Question

好的，我现在检查的是单词的计数。但是我很难按字母顺序排序。

我宁愿这样做，而不只是数它们的数量。

#include <stdio.h>   
#include <stdlib.h> 
#include <string.h> 
typedef struct node *node_ptr; 
typedef struct node {
    int count;
    char *word;
    node_ptr next;
} node_t;  
char *words[] = { "hello", "goodbye", "sometimes", "others", "hello", "others", NULL }; 
node_ptr new_node() {
    node_ptr aNode;
    
    aNode = (node_ptr)(malloc(sizeof(node_t)));
    if (aNode) {
        aNode->next = (node_ptr)NULL;
        aNode->word = (char *)NULL;
        aNode->count = 0;
    }
    return aNode;
}
node_ptr add_word(char *word, node_ptr theList) {
    node_ptr currPtr, lastPtr, newPtr;
    int result;
    int found = 0;
    
    currPtr = theList;
    lastPtr = NULL;
    printf("Checking word:%sn", word);
    
    if (!currPtr) {
        newPtr = new_node();
        if (!newPtr) {
            fprintf(stderr, "Fatal Error. Memory alloc errorn");
            exit(1);
        }
        newPtr->word = word;
        newPtr->next = currPtr;
        newPtr->count = 1;
        found = 1;
        theList = newPtr;
    }
    while (currPtr && !found) {
        result = strcmp(currPtr->word, word); 
        if (result == 0) {
            currPtr->count += 1;
            found = 1;
        } else
        if (result>0) {
            newPtr = new_node();
            if (!newPtr) {
                fprintf(stderr, "Fatal Error. Memory alloc errorn");
                exit(1);
            }
            newPtr->word = word;
            newPtr->next = currPtr;
            newPtr->count = 1;
            if (lastPtr) {
                lastPtr->next = newPtr;
            } else {
                theList = newPtr;
            }
            found = 1;
        } else {
            lastPtr = currPtr;
            currPtr = currPtr->next;
        }
    }
    if ((!found) && lastPtr) {
        newPtr = new_node();
        if (!newPtr) {
            fprintf(stderr, "Fatal Error. Memory alloc errorn");
            exit(1);
        }
        newPtr->word = word;
        newPtr->next = (node_ptr)NULL;
        newPtr->count = 1;
        lastPtr->next = newPtr;
        found = 1;
    }
    return theList; 
}
void printList(node_ptr theList) {
    node_ptr currPtr = theList;
    
    while (currPtr) {
        printf("word: %sn", currPtr->word);
        printf("count: %dn", currPtr->count);
        printf("---n");
        currPtr = currPtr->next; 
    }
}
int main() {
    char **w = words;
    node_ptr theList = (node_ptr)NULL;
    
    printf("Startn");
    while (*w) {
        theList = add_word(*w, theList);
        w++;
    }
    
    printList(theList);
    printf("OK!n");
    return 0;
}

我还想从文件中读取，而不是从单词数组中读取。

FILE *fp;
fp = fopen("some.txt", "w");

我如何使用我创建的结构从文件中读取，然后对它们进行排序?

Answer 1

您可以使用fscanf():

读取文件中的单词

int main(int argc, char *argv[]) {
    node_t *theList = NULL;
    for (int i = 1; i < argc; i++) {
        FILE *fp = fopen(argv[i], "r");
        if (fp != NULL) {
            char word[100];
            while (fscanf(fp, "%99s", word) == 1) {
                theList = add_word(word, theList);
            }
            fclose(fp);
        }
    }
    printList(theList);
    printf("OK!n");
    return 0;
}