///////////////////////////////////////////////////////////////
//
//	assertDemo.cpp
//
//	Demonstrates the use of assertions to enforce
//	preconditions.
//
//	To disable the assert statements (which you would do
//	before shipping the release version of your program),
//	you need to #define the symbol NDEBUG (in this program,
//	just uncomment the #define line).
//
//	You can also induce the compiler to define NDEBUG from
//	the command line, like so:
//
//		g++ -Wall -D NDEBUG -o assertDemo assertDemo.cpp
//	
//
//
//	REVISION HISTORY:
//		4/6/01 (Jeff Ondich) Original version written.
//
///////////////////////////////////////////////////////////////

//#define NDEBUG
#include	<iostream>
#include	<assert.h>

int fib( int n );

int main()
{
	for( int i=1; i <= 10; i++ )
		cout << i << " " << fib( i ) << endl;

	cout << fib( -17 ) << endl;
	
	return 0;
}


///////////////////////////////////////////////////////////////
//
//	Pre-condition:  n >= 1
//
//	Post-condition:  fib returns the nth Fibonacci number.
//
//	Note that this recursive approach is extraordinarily
//	inefficient, and is here just for the purposes of
//	demonstrating assert().
//
///////////////////////////////////////////////////////////////

int fib( int n )
{
	assert( n >= 1 );

	if( n == 1  ||  n == 2 )
		return 1;
	else
		return fib( n - 1 ) + fib( n - 2 );
}