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unleashtheginger/pointer-play.c

Created June 19, 2016 14:10
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Just some (terrible) revision on how structures and pointers work. Next time lists and trees. :)
Raw
pointer-play.c
#include <stdio.h>
void some_pointers()
{
int i = 1;
int *ptr_i;
printf("%d is an integer.\n",i);
printf("%p is a pointer to a memory location.\n",ptr_i);
printf("And has the value: %d.\n",*ptr_i);
ptr_i = &i;
printf("%p is a pointer which now points to i.\n",ptr_i);
printf("So it of course has the value of %d.\n",*ptr_i);
}
void structures_are_cool()
{
printf("Structures are cool.");
struct s_testy {
char *name;
int age;
};
struct s_testy testy;
testy.name = "A Man";
testy.age = 29;
printf("Testy's name is %s and they are %d.\n",testy.name, testy.age);
struct s_testy * ptr_s;
printf("s_ptr points to %p.\n",ptr_s);
ptr_s = &testy;
printf("s_ptr now points to %p.\n",ptr_s);
printf("ptr_s has the values:\n%s.\n%d.\n",ptr_s->name,ptr_s->age);
ptr_s->name = "Cat";
ptr_s->age = 1;
printf("testy now has the values:\n%s.\n%d.\n",testy.name,testy.age);
}
int main(int argc, char** argv)
{
printf("Hello World -- Sunday 19th June 2016 13:50\n");
printf("Just setup tmux and vim to be sensible - 13:56\n");
printf("Now we call some_pointers()\n");
//some_pointers();
//some_pointers();
printf("And now we have some structures - 14:16\n");
structures_are_cool();
printf("And that works. :)\n");
return 0;
}
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