/* ========================================================================== */
/*                                                                            */
/*   structures.c                                                             */
/*   (c) 2017 K. J. Rock                                                      */
/*                                                                            */
/*   This shows how to create and use a structure with pointers               */
/*                                                                            */
/* ========================================================================== */
#include <stdio.h>
#include <stdlib.h>
#include <time.h>

struct db      					// create an employee record
	{
	int id;
	int age;
	double salary;
	};

struct db employee[10];			// create a new database array called employee

int main()
	{
	struct db *ep;       		// introduce a pointer to a structure
	
	// the name of an array is also its address
	ep = employee;     			// point where employee list starts

	// randomize by seeding from time
	srand((unsigned) time(NULL)); 

	// instantiate founder's info 
	// (create and fill the founder's employee record)
	employee[0].id = 42;			// RIP Douglas Adams
   employee[0].age = rand() % 40 + 20;
   employee[0].salary = 25080.15;

	// instantiate the rest of the crew
	for (int i=1; i<10; i++)
		{
      employee[i].id = i;
   	employee[i].age = rand() % 40 + 20;  // no employees under 20 or over 60
   	employee[i].salary = (float) (rand() % 40000 + 20000);
		}

	// scan through array of structures
	for (int i=0; i<10; i++)
		{
		printf("Employee #%2d salary is $%6.2f \n", employee[i].id, employee[i].salary);
		}

	// step through list of structures using pointers
	for (int i=0; i<10; i++)    // repeat 10 times because there are 10 employees
		{
  		printf("Emp #%2d is %2d old earning $%6.2f \n", ep->id, ep->age, ep->salary);
		ep++;  // step to next employee
		}
	}
	
// For the time will come when people will not put up with sound doctrine. 
// Instead, to suit their own desires, they will gather around them a great number 
// of teachers to say what their itching ears want to hear.  Timothy 4:3