如何解析二维指针数组并返回二维指针数组？

Question

抱歉打扰，我正在尝试将像

ANIMAL *animal[2][6]

这样的二维指针数组解析为函数，该函数将返回该二维指针数组。它得到的错误是

[Error] incompatible types in assignment of 'ANIMAL*' to 'ANIMAL* [6]'

P.S：忽略

createNode

功能，因为错误在线

*animal = readFile(animal);

struct ANIMAL {
    char id[10];
    char species[50];
    char type[10];
    char strDate[50];
    time_t create_date = NULL;
    ANIMAL *next;
};

ANIMAL *readFile(ANIMAL *[][6]);
ANIMAL *createNode(ANIMAL *[][6], ANIMAL *, char *, int, int);

int main() {
    ANIMAL *animal[2][6];
    
    for (int j = 0; j < 2; j++) {
        for (int i = 0; i < 6; i++) {
            animal[j][i] = (ANIMAL *)malloc(sizeof(ANIMAL));
            animal[j][i] = NULL;
        }
    }
    *animal = readFile(animal);
}

ANIMAL *readFile(ANIMAL *animal[][6]) {
    FILE *file;
    ANIMAL *temp[1];
    char data[180], date[20];
    int i;
    
    file = fopen("data.txt", "r");
    if (file != NULL) {
        while (fgets(data, sizeof(ANIMAL), file)) {
            temp[0] = (ANIMAL *)malloc(sizeof(ANIMAL));
            char *token = strtok(data, "|");
            strcpy(temp[0]->id, token);
            
            token = strtok(NULL, "|");
            strcpy(temp[0]->species, token);
            
            token = strtok(NULL, "|");
            strcpy(temp[0]->type, token);
            if (strcmp(temp[0]->type, "mamal") == 0)     i = 0;
            if (strcmp(temp[0]->type, "bird") == 0)      i = 1;
            if (strcmp(temp[0]->type, "reptile") == 0)   i = 2;
            if (strcmp(temp[0]->type, "amphibian") == 0) i = 3;
            if (strcmp(temp[0]->type, "insect") == 0)    i = 4;
            if (strcmp(temp[0]->type, "unknown") == 0)   i = 5;
            token = strtok(NULL, "|");
            strcpy(temp[0]->strDate, token);
            
            token = strtok(NULL, "|");
            strcpy(date, token);

            temp[0]->create_date = atoi(date);
            token = strtok(NULL, "|");
            
            *animal = createNode(animal, temp[0], temp[0]->type, i, 2);
        }   
    } else {
        printf("No data found\n");
    }
    fclose(file);
    return *animal;
}

ANIMAL *createNode(ANIMAL *animal[], ANIMAL *temp, char *type, int i, int condition) {
    char buff[20], id[10], species[50];
    time_t now = time(NULL);
    ANIMAL *newNode;
    
    newNode = (ANIMAL *)malloc(sizeof(ANIMAL));
    if (condition == 2) {
        newNode = temp;
        newNode->next = NULL;
        if (animal[i] != NULL) {
            newNode->next = animal[i];
        }
        animal[i] = newNode;
        //printf("/t%d",i);
        return *animal;
    }
    
    newNode->create_date = now;
    strftime(buff, 20, "%Y-%m-%d %H:%M:%S", localtime(&now));
    strcpy(newNode->strDate, buff);

    insert_id:
    printf("\nEnter Animal ID: ");
    scanf(" %[^\n]s", &id);
    if (!validation(animal, id)) {
        goto insert_id;
    }
    strcpy(newNode->id, id);

    printf("Enter Animal Species: ");
    scanf(" %[^\n]s", &species);
    strcpy(newNode->species, species);
    strcpy(newNode->type, type);
    newNode->next = NULL;
    if (animal[i] != NULL) {
        newNode->next = animal[i];
    }
    
    animal[i] = newNode;
    return *animal;
}

在此之前，我使用一维数组并且它有效。改为二维数组后出现错误。我想知道我犯了什么错误以及如何解析和返回 2D 指针数组。

Answer 1

没有理由使用指向

ANIMAL

结构的指针的二维数组。第二个维度似乎对应于动物类型，但第一个维度的使用尚不清楚，可能不需要。

而且

fgets(data, sizeof(ANIMAL), file)

是不正确的，您应该传递

data

字符数组的大小，而不是

ANIMAL

结构的大小。

main

函数应该将数组元素初始化为

NULL

，这可以简单地使用初始化器来完成。

readFile

不需要返回数组指针，让它返回成功/失败指示符。

这是修改后的版本：

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

typedef struct ANIMAL {
    char id[10];
    char species[50];
    char type[10];
    char strDate[50];
    time_t create_date;
    ANIMAL *next;
} ANIMAL;

bool readFile(ANIMAL animals[6]);

ANIMAL *createNode(ANIMAL *[][6], ANIMAL *, char *, int, int);

int main(void) {
    ANIMAL *animal[6] = { NULL, NULL, NULL, NULL, NULL, NULL };

    if (!readFile(animal)) {
       fprintf(stderr, "cannot read animal file\n");
    }
    return 0;
}

const char * const animal_types[5] = { "mamal", "bird", "reptile", "amphibian", "insect" };

int get_animal_type(const char *type) {
    for (int i = 0; i < 5; i++) {
        if (strcmp(type, animal_types[i]) == 0) {
            return i;
        }
    }
    return 5;  /* unknown */
}

bool readFile(ANIMAL animal[6]) {
    char data[180], date[20];
    FILE *file;

    file = fopen("data.txt", "r");
    if (file == NULL) {
        fprintf(stderr, "Cannot open file %s: %s\n", "data.txt", strerror(errno));
        return false;
    }

    while (fgets(data, sizeof(data), file)) {
        ANIMAL *temp = (ANIMAL *)malloc(sizeof(*temp));
        if (temp == NULL) {
            fprintf(stderr, "memory allocation failure\n");
            break;
        }
        char *token = strtok(data, "|");
        if (!token)
            break;
        strcpy(temp->id, token);
        
        token = strtok(NULL, "|");
        if (!token)
            break;
        strcpy(temp->species, token);
        
        token = strtok(NULL, "|");
        if (!token)
            break;
        strcpy(temp->type, token);
        int i = get_animal_type(temp->type);

        token = strtok(NULL, "|");
        if (!token)
            break;
        strcpy(temp->strDate, token);
        
        token = strtok(NULL, "|");
        if (!token)
            break;
        strcpy(date, token);

        temp->create_date = atoi(date);

        createNode(animal, temp, temp->type, i, 2);
    } 
    fclose(file);
    return true;
}

ANIMAL *createNode(ANIMAL *animal[], ANIMAL *temp, char *type, int i, int condition) {
    char buff[20], id[10], species[50], type[10];
    
    if (condition == 2) {
        temp->next = animal[i];
        animal[i] = temp;
        return temp;
    }
    time_t now = time(NULL);
    ANIMAL *newNode = (ANIMAL *)malloc(sizeof(ANIMAL));
    newNode->create_date = now;
    strftime(newNode->strDate, sizeof newNode->strDate, "%Y-%m-%d %H:%M:%S", localtime(&now));

    for (;;) {
        printf("\nEnter Animal ID: ");
        scanf(" %9[^\n]", id);
        if (validation(animal, id))
            break;
    }
    strcpy(newNode->id, id);
    printf("Enter Animal Species: ");
    scanf(" %49[^\n]", species);
    strcpy(newNode->species, species);
    printf("Enter Animal Type: ");
    scanf(" %9[^\n]", type);
    strcpy(newNode->type, type);
    i = get_animal_type(type);
    newNode->next = animal[i];
    animal[i] = newNode;
    return newNode;
}