C语言--error C2075: "arr": 初始化需要带括号的初始化表达式列表。

Question

int main()
{
    int row = 4;
    int col = 5;
    scanf("%d ", &row);
    scanf("%d \n", &col);
    
    int i = 0;
    int j = 0;
    int* arr[] = (int*)malloc(sizeof(int) * row * col);
    for (i = 0; i < row; i++)
    {
        for (j = 0; j < col; j++)
        {
            arr[i][j] = j;
        }
    }
    for (i = 0; i < row; i++)
    {
        for (j = 0; j < col; j++)
        {
            printf("%d", arr[i][j]);
        }
    }
    return 0;
}

这段程序出现error C2075: "arr": 初始化需要带括号的初始化表达式列表。可是如果我在初始化arr的适合，后面不加[],就会出现以下错误：

Answer 1

用这个：

#include<stdio.h>
#include<stdlib.h>
int main()
{
    int row, col;
    scanf("%d", &row);
    scanf("%d", &col);
    int i = 0;
    int j = 0;
    int **arr = (int**)malloc(sizeof(int*) * row);
    for (i = 0; i < row; i++)
    {
        arr[i]=(int*)calloc(col,sizeof(int));
        for (j = 0; j < col; j++)
        {
            arr[i][j] = j;
        }
    }
    for (i = 0; i < row; i++)
    {
        for (j = 0; j < col; j++)
        {
            printf("%d ", arr[i][j]);
        }
        free(arr[i]);
        printf("\n");
    }
    free(arr);
    return 0;
}

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

int main()
{
    int row = 4;
    int col = 5;
    scanf("%d", &row);
    scanf("%d", &col);
    int i = 0;
    int j = 0;
    int (*arr)[col] = (int (*)[col])malloc(sizeof(int) * row * col);
    for (i = 0; i < row; i++)
    {
        for (j = 0; j < col; j++)
        {
            arr[i][j] = j;
        }
    }
    for (i = 0; i < row; i++)
    {
        for (j = 0; j < col; j++)
        {
            printf("%d ", arr[i][j]);
        }
        printf("\n");
    }
    free(arr);
    return 0;
}