/*
   structs_4.c
   create a struct definition
   declare, initialize,  print and free a DYNAMIC ARRAY of structs
   use of the . and -> operators

*/

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

#define INITIAL_ARRAY_MAX 25
#define MAX_NAME_LENGTH 10

typedef struct {
    char *name;
    int  age;
} Person;  /* Person is now a data type */


/* ASSUME INPUT FILE OF THIS FORMAT (alignment unimportant)
Mark  48
Hassan  23
Stephanie 21
Tim 43
Rich 52
*/


int main(int argc, char *argv[])
{
    Person **array;  /* pointer to dynamic array of Person* */
    int i;
    int count = 0;   /* actual # of structs read from file */
    FILE *inFile;
    
    /* temp variables to read data from file */
    char name[MAX_NAME_LENGTH];
    int age;

    if (!(inFile  = fopen("input.txt", "r")))
    {
	fprintf(stderr, "Can't open input.txt!!\n\n");
	exit(1);
    }

    /* allocate the array */
    array = (Person **)malloc(INITIAL_ARRAY_MAX * sizeof(Person *));

    /* populate the array */
    printf("Reading from input.txt\n");
    while(fscanf(inFile,"%s%d",name,&age) == 2)
    {
	printf("reading... %s  %d\n", name, age);
	array[count] = (Person *)malloc(sizeof(Person));
	array[count]->name = (char *)malloc((strlen(name) + 1) * sizeof(char));
	strcpy(array[count]->name, name);
	array[count]->age = age;
	count++;
    }
    fclose(inFile);

    /* print the array */
    printf("\nPrinting the array:\n");
	printf("Slot\tName\tAge\t\n");
    for (i = 0; i < count; i++)
		printf("%2d\t%s\t%2d\n", i, array[i]->name, array[i]->age);
    printf("\n");

    /* free the strings, the structs and then the array */
    for (i = 0; i < count; i++)
    {
	free(array[i]->name);  /* the string */
	free(array[i]);        /* the struct */
    }
    free(array);  /* the dynamic array */

    return 0;
}