1. #include <stdio.h>
2. #include <assert.h>
3. #include <stdlib.h>
4. #include <string.h>
5. struct Person {
6.  char *name;
7.  int age;
8.  int height;
9.  int weight;
10. };
11. struct Person *Person_create(char *name, int age, int height, int weight)
12. {
13.  struct Person *who = malloc(sizeof(struct Person));
14.  assert(who != NULL);
15.  who->name = strdup(name);
16.  who->age = age;
17.  who->height = height;
18.  who->weight = weight;
19.  return who;
20. }
21. void Person_destroy(struct Person *who)
22. {
23.  assert(who != NULL);
24.  free(who->name);
25.  free(who);
26. }
27. void Person_print(struct Person *who)
28. {
29.  printf("Name: %s\n", who->name);
30.  printf("\tAge: %d\n", who->age);
31.  printf("\tHeight: %d\n", who->height);
32.  printf("\tWeight: %d\n", who->weight);
33. }
34. int main(int argc, char *argv[])
35. {
36.  // make two people structures
37.  struct Person *joe = Person_create(
38.  "Joe Alex", 32, 64, 140);
39.  struct Person *frank = Person_create(
40.  struct Person *frank = Person_create(
41.  "Frank Blank", 20, 72, 180);
42.  // print them out and where they are in memory
43.  printf("Joe is at memory location %p:\n", joe);
44.  Person_print(joe);
45.  printf("Frank is at memory location %p:\n", frank);
46.  Person_print(frank);
47.  // make everyone age 20 years and print them again
48.  joe->age += 20;
49.  joe->height -= 2;
50.  joe->weight += 40;
51.  Person_print(joe);
52.  frank->age += 20;
53.  frank->weight += 20;
54.  Person_print(frank);
55.  // destroy them both so we clean up
56.  Person_destroy(joe);
57.  Person_destroy(frank);
58.  return 0;
59. }
60.