correct way to return two dimensional array from a function c

Question

I have tried this but it won\'t work:

#include 

    int * retArr()
    {
    int a[3][3] = {{1,2,3},{4,5,6},{7,8,9}};
    return a;
    }

           


        

Answer 1

We can solve it by using Heap memory / memory allocating using stdlib :

Allocating memory using stdlib can be done by malloc and calloc.

creating array:

• int  ** arr=( int * * ) malloc ( sizeof ( int * ) * 5 ); 
  

  is for allocating 5 rows.

• arr[i]=(int *)malloc(sizeof(int)*5);
  

  is for allocating 5 columns in each "i" row.
• Thus we created arr [ 5 ] [ 5 ].

returning array:

• return arr;
  

We just need to send that pointer which is responsible for accessing that array like above.

#include
#include
int **return_arr()
{
    int **arr=(int **)malloc(sizeof(int *)*5);
    int i,j;
    for(i=0;i<5;i++)//checking purpose
    {
        arr[i]=(int *)malloc(sizeof(int)*5);
        for(j=0;j<5;j++)
        {
            arr[i][j]=i*10+j;
        }
    }
    return arr;
}
int main()
{
    int **now;
    now=return_arr();
    int i,j;
    for(i=0;i<5;i++)
    {
        for(j=0;j<5;j++)
        {
            printf("%d ",now[i][j]);
        }
        printf("\n");
    }
    return 0;
}