automatic music composer with rand()

iKurzweil.m

//
//  main.m
//  iKurzweil
//
//  Created by Jaroslaw Szpilewski on 28/7/11.
//  Copyright 2011 Flux Forge. All rights reserved.
//

#import <Foundation/Foundation.h>

#define NOTE_A 440.0
double ratios[] = {
	(1.0/2.0),
	(4.0/3.0),
	(3.0/4.0),
	(1.0/5.0),
	(2.0/1.0),
};

double give_funky_note(double seed)
{
	size_t s = sizeof(ratios)/sizeof(double);
	int r = rand()%s;

	return seed * ratios[r];
}

NSString *note_name_for_frequency(double freq)
{
	NSString *ret = nil;

	/* anders:
	 1. note rauskriegen mit modulo von grundnote
	 2. oktave mit div von grundoktave
	 */
	
	int r = freq;
	if (r == 88)
		return @"F-2";
	if (r == 220)
		return @"A-3";
	if (r == 247)
		return @"B-3";
	if (r >= 260 && r <= 264)
		return @"C-4";
	if (r == 293)
		return @"D-4";
	if (r == 330)
		return @"E-4";
	if (r == 371)
		return @"F#4";
	if (r == 391)
		return @"G-4";
	if (r == 440)
		return @"A-4";
	if (r == 495)
		return @"B-4";
	if (r == 521)
		return @"C-5";
	if (r == 586)
		return @"D-5";
	if (r == 660)
		return @"E-5";
	if (r == 695)
		return @"F-5";
	if (r == 782)
		return @"G-5";
	if (r == 880)
		return @"A-5";
	if (r == 990)
		return @"B-5";
	if (r == 1042)
		return @"C-6";
	if (r == 1173)
		return @"D-6";
	if (r == 1320)
		return @"E-6";
	
	return ret;
}

int main (int argc, const char * argv[])
{

	@autoreleasepool {

		srand(time(0));
		double seed_note = give_funky_note(NOTE_A);
		for (int i = 0; i < 32; i++) {
			printf("[%i]\t%.2f = %s\n",i, seed_note, [note_name_for_frequency(seed_note) cStringUsingEncoding: NSUTF8StringEncoding]);
			for (;;) {
				int prev = seed_note;
				seed_note = give_funky_note(seed_note);
				if ((int)seed_note != prev)  // uncomment to disable n same notes in a row
					break;
			}
			if (seed_note < NOTE_A/2.0)
				seed_note = NOTE_A;
			if (seed_note > NOTE_A*3.0)
				seed_note = NOTE_A;
		}
	    
		
	}
    return 0;
}