question on pointer

[blob84]

This code works, but i don't understand why the loop works.

#include <stdio.h>
#include <stdlib.h>
int main() {
	char **arr;
	size_t size = 200 * sizeof(size);
	arr = malloc(size);
	arr[0] = "cane";
	arr[1] = "dog";
	while( *arr != NULL )
		printf("%s\n", *arr++);

}

[msh]

!= is saying not.
The code can be further reduced.

while (*arr++) {
    printf("%s\n", *arr);
}

[blob84]

nice msh, but inverting arr position:

while (*arr) 
      printf("%s\n", *arr++);

[msh]

nice msh, but inverting arr position:

while (*arr) 
      printf("%s\n", *arr++);

Yea. You're right.

But you can't really use this here; it'll segfault if it fails to run across a null byte before reaching the end of arr.

This is probably more correct.

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

int main(void)
{
    const int entries = 2;
    char** arr = (char**)malloc(entries * sizeof(*arr));
    arr[0] = "cane";
    arr[1] = "dog";

    int i;
    for (i = 0; i < entries; ++i)
    {
        printf("%s\n", arr[i]);
    }

    return 0;
}