ex16.c

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

struct Person {
	char* name;
	int height;
	int weight;
	int age;
};

struct Person create_person_on_stack(char* name, int age, int height, int weight) {

	struct Person who;

	who.name = name;
	who.age = age;
	who.height = height;
	who.weight = weight;

	return who;
}

void print_person_from_stack(struct Person who) {

	printf("Name: %s\n", who.name);
	printf("Age: %d\n", who.age);
	printf("Height: %d\n", who.height);
	printf("Weight: %d\n\n", who.weight);
}

struct Person* create_person(char* name, int age, int height, int weight) {

	struct Person* who = malloc(sizeof(struct Person));

	assert(who != NULL);

	who->name = strdup(name);
	who->age = age;
	who->height = height;
	who->weight = weight;

	return who;
}

void destroy_person(struct Person* who) {

	assert(who != NULL);
	free(who->name);
	free(who);
}

void print_person(struct Person* who) {

	printf("Name: %s\n", who->name);
	printf("Age: %d\n", who->age);
	printf("Height: %d\n", who->height);
	printf("Weight: %d\n\n", who->weight);
}

int main(int argc, char* argv[]) {

	struct Person* joe = create_person("Joe Alex", 21, 180, 80);
	struct Person* frank = create_person("Frank Viola", 45, 178, 90);

	struct Person jonas = create_person_on_stack("Jonas Erhart", 21, 181, 70);

	printf("Joe is at memory location %p.\n", joe);
	printf("size of joe is %lu\n", sizeof(*joe));
	print_person(joe);

	printf("Frank is at memory location %p.\n", frank);
	printf("size of frank is %lu\n", sizeof(*frank));
	print_person(frank);

	printf("Jonas is at memory location %p.\n", &jonas);
	printf("size of jonas is %lu\n", sizeof(jonas));
	print_person_from_stack(jonas);

	joe->age += 20;
	frank->age += 10;
	jonas.age += 1;

	print_person(joe);
	print_person(frank);
	print_person_from_stack(jonas);

	destroy_person(joe);
	destroy_person(frank);
	// no need to free jonas

	return 0;
}