/*
Program STRUCTURE-TEST #0

Basic structure handling

Version 1.0 / 2001.10.01
Autor: Peter Schindler, pstrainer@gmx.net
*/

/* compiler option: version 1...4	*/
#define version 1

/* security check */
#ifndef version
#define version 1
#endif
#if ((version<1)||(version>4))
#define version 1
#endif

/* standard libraries */
#include <stdio.h>
#include <conio.h>

/* structure definition */
struct teststruc {
	int sernr;
	int demo;
};

/* function definitions in different versions */
void print_header (char *);
void print_trailer (void);

#if (version<=1)
void printstruc (teststruc);
void changestruc (teststruc);
#else
void printstruc (teststruc *);
void changestruc (teststruc *);
#endif

/********** main **********/
void main (void) {
	char myname[]="STRUCTURE-TEST #0";
	// declare tsa of type teststruc
	teststruc tsa;

	print_header(myname);

	/* how to handle structure variables */
	tsa.sernr = 90;
	tsa.sernr+= 9;
	tsa.demo= 900 + tsa.sernr;

	/* print structure, change it, print again
	   in 4 versions:							*/
#if (version<=1)
	// copy structure to sub-function
	printstruc (tsa);
	changestruc (tsa);
	printstruc (tsa);
#else
	// copy pointer to structure to sub-function
	printstruc (&tsa);
	changestruc (&tsa);
	printstruc (&tsa);
#endif

	print_trailer();
}

/* functions printstruc and changestruc in 4 different versions */

#if (version<=1)
// we get a copy (!) of the structure itself:
void printstruc (teststruc a) {
	int i,j;
	printf("version %d: ",version);
	i=a.sernr;
	j=a.demo;
	printf("i=%d j=%d\n",i,j);
}
void changestruc (teststruc a) {
	a.sernr-=9;
	a.demo-=99;
}
#endif

#if (version==2)
// we get a pointer to the structure
// we copy the structure to our own structure
// we work with our own structure
// we copy the result to the original structure
void printstruc (teststruc *pa) {
	int i,j;
	teststruc b;
	printf("version %d: ",version);
	b=*pa;
	i=b.sernr;
	j=b.demo;
	printf("i=%d j=%d\n",i,j);
}
void changestruc (teststruc *pa) {
	teststruc b;
	b=*pa;
	b.sernr-=9;
	b.demo-=99;
	*pa=b;
}
#endif

#if (version==3)
// we get a pointer to the structure
// we work with the structure using pointers
void printstruc (teststruc *pa) {
	int i,j;
	printf("version %d: ",version);
	i=(*pa).sernr;
	j=(*pa).demo;
	printf("i=%d j=%d\n",i,j);
}
void changestruc (teststruc *pa) {
	(*pa).sernr-=9;
	(*pa).demo-=99;
}
#endif

#if (version>=4)
// we get a pointer to the structure
// we work with the structure using -> pointers
void printstruc (teststruc *pa) {
	int i,j;
	printf("version %d: ",version);
	i=pa->sernr;
	j=pa->demo;
	printf("i=%d j=%d\n",i,j);
}
void changestruc (teststruc *pa) {
	pa->sernr-=9;
	pa->demo-=99;
}
#endif

void print_header (char *header) {
#ifdef _DEBUG
	printf("Debug version ");
#else
	printf("Release version ");
#endif
	printf("of program %s\n\n",header);
}

void print_trailer (void) {
#ifdef _DEBUG
	/*	show console window until key pressed	*/
	printf("\nPress any key to continue ");
	_getch();
#endif
}

/* ========== eof ========== */