#include <stdio.h>
#include <stdlib.h>	// need for *alloc

// much easier to always use typedef when defining structs:
typedef struct {
	int n1, n2, n3;
} SSN;				// SSN is new type name

char *ssnString(SSN s);

int main(void)
{
	SSN *n1p, person;
	person.n2 = 54;
	n1p = malloc(sizeof(SSN));	// works without typecast
	n1p->n1 = 100;
	n1p->n2 = 40;
	n1p->n3 = 50;
	printf("%03d-%2.2d-%04d\n", n1p->n1, n1p->n2, n1p->n3);
	puts(ssnString(*n1p));
	printf("enter SSN in form ###-##-####\n");
	scanf("%d-%d-%d", &n1p->n1, &n1p->n2, &(n1p->n3));
	puts(ssnString(*n1p));

	printf("enter SSN in 3 integer parts: ");
	scanf("%d %d %d", &person.n1, &person.n2, &person.n3);
	printf("%03d-%02d-%04d\n", person.n1, person.n2, person.n3);

	int red;
	printf("enter SSN as ###-##-#### ");
	red = scanf("%3d-%2d-%4d", &person.n1, &person.n2, &person.n3);
	printf("\nred %d values\n", red);
	printf("%03d-%02d-%04d\n", person.n1, person.n2, person.n3);

	char word[20];
	printf("enter word: ");
	scanf("%s", word);
	printf("word was: %s\n", word);

	return 0;
}

char *ssnString(SSN ssn)
{
// char st[] = calloc(5, sizeof(char)); // ERROR - must use pointer notation

// memory leak
char *s = calloc(12, sizeof(char)); // might need typecast (char *)


	sprintf(s, "%03d-%02d-%04d", ssn.n1, ssn.n2, ssn.n3);
	/*
	s[3] = '-';
	s[6] = '-';
	s[11] = '\0';
	s[0] = (char) (ssn.n1 / 100 + '0');
	s[1] = (char) (ssn.n1 / 10 % 10 + '0');
	s[2] = (char) (ssn.n1 % 10 + '0');
	s[4] = (char) (ssn.n2 / 10 + '0');
	s[5] = (char) (ssn.n2 % 10 + '0');
	s[7] = (char) (ssn.n3 / 1000 + '0');
	s[8] = (char) (ssn.n3 / 100 % 100 + '0');
	s[9] = (char) (ssn.n3 / 10 % 10 + '0');
	s[10] = (char) (ssn.n3 % 10 + '0');
	*/
	return s;
}