comptune.c

#include <stdio.h>
#include <string.h>
static const char *major_tune_strs[2][12]=
{
	{"C", "Db", "D", "Eb", "E",	"F", "F#", "G", "Ab", "A", "Bb", "B"},
	{"C", "C#", "D", "D#", "E",	"F", "Gb", "G", "G#", "A", "A#", "B"},
};



static const char *minor_tune_strs[2][12] = 
{
	{"Am", "Am#", "Bm", "Cm", "Cm#", "Dm", "Dm#", "Em", "Fm", "Fm#", "Gm", "Gm#"},
	{"Am", "Bmb", "Bm", "Cm", "Dmb", "Dm", "Emb", "Em", "Fm", "Gmb", "Gm", "Amb"}
};

static int tunestr2idx( const char *str)
{
	int i,j;
	const char **alltunes[4];
	alltunes[0]= major_tune_strs[0];

	alltunes[1] = major_tune_strs[1];
	alltunes[2] = minor_tune_strs[0];
	alltunes[3] = minor_tune_strs[1];

	for ( j=0; j<4; j++) {
		const char **tunestr = alltunes[j];
		for ( i=0; i<12; i++) {
			if ( strcmp( tunestr[i], str)==0) 
				return i;
		}
	}
	return -1;
}

int tune_subtract( const char *comptune, const char *basetune)
{
	int bt, ct;
	bt = tunestr2idx( basetune);
	ct = tunestr2idx( comptune);
	if ( bt==-1 || ct==-1) 
		return -999;
	return ct-bt;
}

int main ( int argc, char *argv[])
{
	const char *basetune, *comptune, *cp;
	int compd, pitchd;
	basetune = argv[2];
	comptune = argv[1];

	switch (comptune[0]) {
		case '+':
			cp = comptune +1;
			compd=12;
			break;
		case '-':
			cp = comptune + 1;
			compd=-12;
		default:
			cp = comptune;
			compd=0;
	}
	pitchd = tune_subtract( cp, basetune) + compd;
	printf("comptune(%s) - basetune(%s) = %d\n", comptune, basetune, pitchd); 
	return 0;
}