Pass a 2-D array as an argument to function

Question

If I dont know the size of both the dimensions of array and want to print a matrix using the following code

    
    void printAnyMatrix(int (*A)[], int size_A, int size_B)
    {
       for (int i = 0; i<=size_A; i++)
       {
           for (int j = 0; j<=size_B; j++)
               printf("%d ", A[i][j]);
           printf("\n");
       }
       printf("\n");
    }
    

Compiler gives

error cannot convert ‘int (*)[(((unsigned int)((int)size_B)) + 1)]’ to ‘int ()[]’ for argument ‘1’ to ‘void printAnyMatrix(int ()[], int, int)

Answer 1

Use template feature for such problems:

template<typename T, unsigned int size_A, unsigned int size_B>
void printAnyMatrix(T  (&Arr)[size_A][size_B])
{       // any type^^  ^^^ pass by reference        
}

Now you can pass any 2D array to this function and the size will be automatically deduced in the form of size_A and size_B.

Examples:

int ai[3][9];
printAnyMatrix(ai);
...
double ad[18][18];
printAnyMatrix(ad);

Answer 2

Simplify the signature: a pointer is simpler to read by humans.

You also have an error in the loops: it's less then, not less or equal.

void printAnyMatrix(int *A, int size_A, int size_B)<br />
{
   for (int i = 0; i<size_A; i++)
   {
       for (int j = 0; j<size_B; j++)
           printf("%d ", A[i*size_B + j]);
       printf("\n");
   }
   printf("\n");
}