More Goats #
- Talk about stars and arrows.
- Array of goats.
- Herd struct.
- Fixed size herd.
- Variable sized herd.
- Can’t pass an array to a function.
- Can pass a herd to a function, either fixed or variable sized.
Linked Lists #
If we just had structs and no arrays we could still program.
Linked lists are sometimes simpler since we can add an item in actual O(1) time.
Stuff to cover:
- Handling a linked list with a for loop.
- Header files, include guards, modules.
- Include quotes vs angle brackets.
- The concept of “ownership”, explicitly.
- Passing a value by reference vs. by value.
- Arrow vs dot in structs.
- The “java” pattern (all refs).
- Memory layouts of different structures.
#include <stdio.h>
#include <stdlib.h>
typedef struct cons_cell {
int head;
struct cons_cell* tail;
} cons_cell;
cons_cell* empty = (cons_cell*) 0;
cons_cell*
cons(int xx, cons_cell* ys)
{
cons_cell* cell = malloc(sizeof(cons_cell));
cell->head = xx;
cell->tail = ys;
return cell;
}
void
list_free(cons_cell* xs)
{
if (xs) {
list_free(xs->tail);
free(xs);
}
}
int
main(int argc, char* argv[])
{
cons_cell* xs = empty;
for (int ii = 0; ii < 10; ++ii) {
xs = cons(ii, xs);
}
cons_cell* ys = xs;
for (int ii = 0; ii < 5; ++ii) {
ys = ys->tail;
}
ys = cons(35, ys);
printf("\nfirst list:\n");
for (cons_cell* it = xs; it; it = it->tail) {
printf("%d\n", it->head);
}
printf("\n2nd list:\n");
for (cons_cell* it = ys; it; it = it->tail) {
printf("%d\n", it->head);
}
list_free(xs);
free(ys);
return 0;
}
Games example.
typedef struct game {
char* team1_name;
int team1_score;
char* team2_name;
int team2_score;
} game;
typedef struct season {
game games[3];
} season;
- Plymouth Panthers
- Fitchburg Falcons
- Massachusetts Maritime Buccaneers
- Castleton Spartans
