//-------------------------------------------------------------------
//	12throot.cpp
//
//	This program computes and displays the frequencies of notes
//	on the standard American piano having 88 keys.  The program
//	output has C-language syntax (for redirection as a header).   
//
//		  compile using:  $ make 12throot
//		  execute using:  $ 12throot > pianokey.h
//
//	programmer: ALLAN CRUSE
//	written on: 22 JUN 2005
//	revised on: 17 SEP 2005 -- to show the names of these tones
//-------------------------------------------------------------------

#include <stdio.h>	// for printf(), perror() 
#include <math.h>	// for log() and exp()

char 	*notename[] = 
{ "A", "A#", "B", "C", "C#", "D", "D#", "E", "F", "F#", "G", "G#" };

int main( int argc, char **argv )
{
	double		radicand = 2.0;
	double		root12th;

	// print a file-header showing filename and computed values
	printf( "// <pianokey.h> \n//\n" );
	root12th = exp( log( radicand )/12.0 );
	printf( "// Twelfth-root of 2 is %0.5f \n", root12th );	
	
	// check for inaccuracy in the accumulated rounding error
	double		check = 1.0;
	for (int i = 0; i < 12; i++) check *= root12th;
	printf( "// Twelfth power equals %0.5f \n//\n", check );

	// compute and print the array of piano-key frequencies 
	double		note = 27.5;
	printf( "\ndouble\tpianokey[] = { " );
	for (int i = 0; i < 88; i++)
		{
		printf( "\n\t\t\t %4.5f", note );
		if ( i == 87 ) printf( " \t" ); else printf( ",\t" );
		printf( " /*  %-2s */ ", notename[ i % 12 ] );	
		note *= root12th;
		}
	printf( " };\n\n" );
}