pointer output confusion

[unoho]

code:

#include <stdio.h> #include <string.h> typedef struct road_trip {         char place [30];         struct road_trip* next; }trip; int main (void) {         trip s1, s2, s3, s4, s5;         trip *ptr; strcpy (s1.place, "Long Point"); strcpy (s2.place, "Niagara Falls"); strcpy (s3.place, "Pelee Island"); strcpy (s4.place, "Port Burwell"); strcpy (s5.place, "Port Dover"); s5.next = &s1; ptr = &s2; s1.next = &s4; s3.next = NULL; s4.next = &s3; s2.next = &s5; while (ptr != NULL) { printf ("%s\n", ptr -> place); ptr = ptr -> next; } return (0); }

output is:
Niagara Falls
Port Dover
Long Point
port burwell
pelee island

could anyone please explain the output to me. im kinda lost,, maybe im overthinking
thanks

[TerranceN]

At the start of the program:

ptr goes to NULL

Long Point goes to NULL
Niagara Falls goes to NULL
Pelee Island goes to NULL
Port Burwell goes to NULL
Port Dover goes to NULL

After you change ptr and next values:

ptr goes to Niagara Falls

Long Point goes to Port Burwell
Niagara Falls goes to Port Dover
Pelee Island goes to NULL
Port Burwell goes to Pelee Island
Port Dover goes to Long Point

Now just follow from ptr until NULL. In case you didn't know this, what you are creating is called a linked list. Hope that helps.

[unoho]

oh,, I already got it but thanks for your answer...
I just had to look up some notes on pointers,,

thnks again