Help me fix this code

Question

Objective - To create a program that uses double pointer to accept the input of a 2D array through a function and prints it in reverse order

My code -

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

int pointer_reverser(char** array);

int main()
{
clrscr();
char arr[3][3];
printf("Please enter 9 elements to be entered in a 3 by 3 array: ");
for (int i=0;i<3;i++)
{
for (int j=0;j<3;j++)
{
scanf("%c",&arr[i][j]);
}
}
printf("Thank you for your input. Here is your reversed array: ");

pointer_reverser(*arr);

getch();
}

int pointer_reverser(char** array)
{
char* ptr1 = NULL;
char** ptr2 = NULL;
ptr1 = array[3][3];
ptr2 = &ptr1;
for (int i=0;i<3;i++)
{
for (int j=0;j<3;j++)
{
printf("%c", *ptr1);
ptr1--;
}
ptr2 = &ptr1;
}
}

I get a segmentation fault mid-program when compiling and running with GDB Online

Answer 1

Make note that when you decrement a pointer you get back in memory by 1*memory pointed size and because you use char**, you get back by 4 (or 8) bytes not 1 like you expected... Anymore, try this code:

int pointer_reverser(char array[3][3]) {
// because array is a 3x3=9 matrix and you have to point
// to last element, we make the adress of last element
// by adding first element address + element_count - 1 = 8
// Note that i converted array to char* for what i said before
char* ptr1 = ((char*)array)+8;

for (int i=0; i<3; i++) {
for( int j=0; j<3; j++, ptr1-- ){
printf("%c", *ptr1);
}
printf("\n");

}
}