使用带有动态分配的C从CSV读取和保存值

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

#define MAX_LINE_LENGTH 1000
#define MAX_FIELD_LENGTH 100

typedef struct {
    char** fields;
    int num_fields;
} Record;

Record* read_csv(const char* filename, int* num_records) {
    FILE* file = fopen(filename, "r");
    if (file == NULL) {
        printf("Failed to open file: %s\n", filename);
        return NULL;
    }

    char line[MAX_LINE_LENGTH];
    int max_records = 100;
    Record* records = (Record*)malloc(max_records * sizeof(Record));
    *num_records = 0;

    while (fgets(line, sizeof(line), file) != NULL) {
        if (*num_records >= max_records) {
            max_records *= 2;
            records = (Record*)realloc(records, max_records * sizeof(Record));
        }

        Record* record = &records[*num_records];
        record->fields = (char**)malloc(MAX_FIELD_LENGTH * sizeof(char*));
        record->num_fields = 0;

        char* field = strtok(line, ",");
        while (field != NULL) {
            record->fields[record->num_fields] = strdup(field);
            record->num_fields++;
            field = strtok(NULL, ",");
        }

        (*num_records)++;
    }

    fclose(file);
    return records;
}

void save_csv(const char* filename, Record* records, int num_records) {
    FILE* file = fopen(filename, "w");
    if (file == NULL) {
        printf("Failed to open file: %s\n", filename);
        return;
    }

    for (int i = 0; i < num_records; i++) {
        Record* record = &records[i];
        for (int j = 0; j < record->num_fields; j++) {
            fprintf(file, "%s", record->fields[j]);
            if (j < record->num_fields - 1) {
                fprintf(file, ",");
            }
        }
        fprintf(file, "\n");
    }

    fclose(file);
}

int main() {
    int num_records;
    Record* records = read_csv("data.csv", &num_records);

    // Process the records...

    save_csv("output.csv", records, num_records);

    // Clean up the memory
    for (int i = 0; i < num_records; i++) {
        Record* record = &records[i];
        for (int j = 0; j < record->num_fields; j++) {
            free(record->fields[j]);
        }
        free(record->fields);
    }
    free(records);

    return 0;
}