CAN YOU PLEASE EXPLAIN STEP BY STEP

13. What is the output of the following program? #include typedef struct fred int barney 121: struct fred next; fred; int main (void) fred f1, f2, f3, f4: fred* x; f4.next- &f2: f1.barney [0]-3; f2.next?&f1; f3.barneylo]-2: fl.next = NULL ; fl.barney [1)-5; f2.barney [O]#7; f2.barney [ 11-6; f3.barney[1]-4: f4.barney [oj-9; f4.barney[1]-8; while (x != NULL) printf ("%d ", xx-> next: x-> barney [O]); return (0)