c - 'int *' differs in levels of indirection from ' int'

Question

我正在尝试运行此代码；编译代码很好，有一些警告，但是当我尝试运行它时它就会崩溃。这是我尝试运行的代码:

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

struct maze_data{
    int* maze_array;
    int* start_location;
    int* end_location;
    int* rows;
    int* columns;
};

struct maze_data get_data(void);

void main(){

    struct maze_data data_object;

    data_object = get_data();

}

struct maze_data get_data(void) {
    char c;
    int i = 0;
    int j = 0;
    int k = 0;
    int numberlength = 0;
    char number[2];
    int size_of_file;
    int number_of_numbers;
    char characters_in_file[100000]; 
    int numbers_in_file[100000];
    int space_locations[100000];
    char fname[100] = "";
    int rows;
    int columns;
    int mazenumbers[1000][1000];
    struct maze_data data_object;
    int start[2];
    int end[2];

    printf("enter file name: ");                
    gets(fname);

    FILE *fpoint;
    fopen_s(&fpoint, fname, "r+");              
    if (fpoint == NULL) {                       
        printf("No Such File !! ");
        return;
    }

    while (1) {
        c = fgetc(fpoint);                      
        if (feof(fpoint)) {
            printf("\n");
            size_of_file = i - 1;               
            break;
        }
        characters_in_file[i] = c;
        i++;
    }

    for (i = size_of_file; i >= 0; i--) {
        characters_in_file[i + 1] = characters_in_file[i];
    }
    characters_in_file[0] = ' ';

    for (i = 0; i < (size_of_file + 1); i++) {
        if (characters_in_file[i] == '\n'  || characters_in_file[i] == ' ') {
            space_locations[j] = i;
            j++;
        }
    }
    number_of_numbers = j - 1;

    for (i = 0; i < number_of_numbers; i++) {
        numberlength = (space_locations[i + 1] - 1) - (space_locations[i]);
        number[0] = characters_in_file[space_locations[i]+1];
        if (numberlength == 2) {
            number[1] = characters_in_file[space_locations[i + 1] - 1];
        }   
        else {
            number[1] = ' ';
        }
        if (numberlength > 0) {
            j = atoi(number);
            numbers_in_file[i] = j;
        }
    }

    for (i = 0; i < number_of_numbers; i++) {
        if (numbers_in_file[i] < 0) {
            for (j = 0; j < number_of_numbers; j++) {
                numbers_in_file[j + i] = numbers_in_file[j + i + 1];
            }
            number_of_numbers--;
        }
    }

    rows = numbers_in_file[0];
    columns = numbers_in_file[1];
    start[0] = numbers_in_file[2];
    start[1] = numbers_in_file[3];
    end[0] = numbers_in_file[4];
    end[1] = numbers_in_file[5];

    k = 7;
    for (i = 0; i < rows; i++) {
        for (j = 0; j < columns; j++) {
            mazenumbers[i][j] = numbers_in_file[k];
            k++;
        }
    }

    data_object.maze_array = mazenumbers;
    data_object.start_location = start;
    data_object.end_location = end;
    data_object.rows = rows;
    data_object.columns = columns;

    return data_object;
}

我收到这些错误:

(38):警告 C4013:“获取”未定义；假设 extern 返回 int

(44):警告 C4033:“get_data”必须返回一个值

(123): 警告 C4047: '=': 'int *' 与

的间接级别不同

'int(*)[1000]'

(126): 警告 C4047: '=': 'int *' 与 'int' 的间接级别不同

(127): 警告 C4047: '=': 'int *' 与 'int' 的间接级别不同

(131):警告 C4715:“get_data”:并非所有控制路径都返回值

有人可以解释一下出了什么问题吗？谢谢。

Answer 1

get_data() 被定义为返回 struct maze_data，因此它必须始终这样做，即使在错误情况下也是如此:

if (fpoint == NULL) {
    printf("No Such File !! ");
    return;
}

由于这是检查可能致命的错误，因此修复它的一个简单方法是将 return 替换为 exit(1);

您将结构定义为具有指向整数的指针:

struct maze_data {
    int* maze_array;
    int* start_location;
    int* end_location;
    int* rows;
    int* columns;
}

然后尝试将一组数组分配给一个指针:

int mazenumbers[1000][1000];

data_object.maze_array = mazenumbers;

以及其他指针的整数值:

int rows;
int columns;

data_object.rows = rows;
data_object.columns = columns;

对于行和列，看起来您应该将结构定义更改为

int rows;
int columns;

对于 maze_array，这完全取决于您想要返回的内容...是整个 mazenumbers 数组数组，还是只是某一行？无论哪种方式，如果要返回指向内存的指针，您都无法为 mazenumbers 静态分配内存，您将需要使用 malloc() 为 mazenumbers 分配堆内存它。