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

/* A C Structure is a collection of variables that are held together containing
linked or related information about something. If this sounds very much like an
object without the associated code (methods), you're right ;-) */

#define MAXROOMS 5

/* We'll set up a structure called an "R" ... a pointer to it is a "ROOM" */

typedef struct { int roomno;
        float d_price; float s_price;
        char faces; } R, *ROOM ;

/* A function into which we pass a pointer to a structure ... we can then access
members within the structure using the -> notation */

float doubleoffset(ROOM current) {
        return current->d_price - current->s_price; }

main() {

        ROOM honeymoon; /* A couple of pointers */
        ROOM garden;

        float extrabrekkie; int roomcount; int k;
        roomcount = MAXROOMS;

                        /* Allocate memory for a structure for each initial room */

        honeymoon = calloc(roomcount,sizeof(R));

        for (k=0; k<roomcount; k++) {
                (honeymoon+k)->roomno = k+1;
                (honeymoon+k)->d_price = 95.00; (honeymoon+k)->s_price = 85.00;
                (honeymoon+k)->faces = 'E';
                if (k==0) (honeymoon+k)->faces = 'S';
                if (k==4) (honeymoon+k)->faces = 'N'; }

                        /* And extend that memory to allow for three garden rooms too */

        honeymoon = realloc(honeymoon,(roomcount+3) * sizeof(R));
        garden = honeymoon + roomcount;
        for (k=0; k<3; k++) {
                (garden+k)->roomno = k+21;
                (garden+k)->d_price = 65.00; (garden+k)->s_price = 45.00;
                (garden+k)->faces = 'W'; }
        roomcount += 3;

                        /* Loop through ALL the rooms, outputting data from each of them */

        for (k=0; k<roomcount; k++) {
                extrabrekkie = doubleoffset(honeymoon+k);
                printf("\nRoom number %d\n",(honeymoon+k)->roomno);
                printf("The room costs up to %.2f per night\n", (honeymoon+k)->d_price);
                printf("Single offset for this room - %.2f\n",extrabrekkie);
                printf("Looks %c \n",(honeymoon+k)->faces);
        }
}

/* Sample compile and output

munchkin:capr grahamellis$ gcc -o sixteen sixteen.c
munchkin:capr grahamellis$ ./sixteen

Room number 1
The room costs up to 95.00 per night
Single offset for this room - 10.00
Looks S

Room number 2
The room costs up to 95.00 per night
Single offset for this room - 10.00
Looks E

Room number 3
The room costs up to 95.00 per night
Single offset for this room - 10.00
Looks E

Room number 4
The room costs up to 95.00 per night
Single offset for this room - 10.00
Looks E

Room number 5
The room costs up to 95.00 per night
Single offset for this room - 10.00
Looks N

Room number 21
The room costs up to 65.00 per night
Single offset for this room - 20.00
Looks W

Room number 22
The room costs up to 65.00 per night
Single offset for this room - 20.00
Looks W

Room number 23
The room costs up to 65.00 per night
Single offset for this room - 20.00
Looks W
munchkin:capr grahamellis$

*/