Chopiner

So, I'm learning Chopin's piano concerto in e, and wrote something simple up to help with the complicated rhythms. If you're ever having rhythm trouble, just compile it in GCC or any other C++ compiler and the rest should be pretty self-explanatory. You'll have to #include iostream, sstream, vector, cmath and assert.h.


using namespace std;
string LH;
string RH;
int nSubBeats;
int timeSig;

struct noteT {
double value;
bool rest;
double position;
};

string GetLine() {
string result;
getline(cin, result);
return result;
}

int GetInteger() {
while(true) {
stringstream converter;
converter << GetLine();

int result;
converter >> result;

if(converter.fail())
cout << "Please enter an integer. ";
else {
char remaining;
converter >> remaining;

if(converter.fail())
return result;
else
cout << "Unexpected character: " << remaining << endl;
}

cout << "Retry: ";
}
}

double Abs(double n) {
return (n<0) ? -n : n;
}

bool CloseEnough(double sum) {
return Abs(1 - sum) < .01;
}

double LCM(double a, double b) {
double A = a;
double B = b;
while (!CloseEnough(1.0-(a-b)))
(a < b) ? a += A : b += B;
return ((int)a - a == 0) ? a : b;
}

int Round(double n) {
int flooring = floor(n);
int ceiling = ceil(n);
return (n - flooring < ceiling - n) ? flooring : ceiling;
}

void PrintfBeat(string hand) {
for (size_t i = 0; i < hand.length(); i++)
hand[i] = '-';

int every = hand.length()/timeSig;
for (size_t i = 0; i < timeSig; i++)
hand[i*every] = '!';

cout << "(The first line is the beat)\n" << hand << endl;
return;
}

void CalculateNoteValue(const string source, noteT &currNote, const int i, int &n) {
while (true) {
if (source[i+n] == '_')
currNote.value /= 2;
else if (source[i+n] == '-')
currNote.value *= 2;
else if (source[i+n] == '.')
currNote.value *= 1.5;
else {
n--;
return;
}
n++;
}

return;
}

double FindModifier(const string source, int &n) {
double modifier = 1;
n++;
while (source[n] == '_' || source[n] == '.' || source[n] == '-' ) {
if (source[n] == '_')
modifier *= .5;
if (source[n] == '.')
modifier *= 1.5;
if (source[n] == '-')
modifier++;
n++;
}
n--;
return modifier;
}

double WhatsTheKPlet(const string source, int &i);

double kPletBracketsSituation(const string source, int i) {
vector bracketedNotes, total;
while (source[i] != ')') {
double currentNoteValue = FindModifier(source, i);
bracketedNotes.push_back(currentNoteValue);
i++;
}

if (source[i+1] != '<') {
int increment;
for (size_t j = 0; j < bracketedNotes.size(); j++) { // Slightly inefficient but more readable and no copied code.
increment = 1;
noteT dummy;
dummy.value = bracketedNotes[j];
CalculateNoteValue(source, dummy, i, increment);
total.push_back(dummy.value);
}
i += increment;
} else if (source[i+1] == '<') {
i += 2;
double kPlet = WhatsTheKPlet(source, i);
string number = "     ";
double divideBy;
int n = 0;
while (source[i+n] != '>') {
number[n] = source[i+n];
n++;
}
i += n;

divideBy = atof(number.c_str());
double multiplier = divideBy/kPlet;

for (size_t j = 0; j < bracketedNotes.size(); j++)
total.push_back(bracketedNotes[j]*multiplier);

} else {
cout << "\nBad input: char \'" << source[i+1] << "\' after \')\'.\nSIGABRT time! Wheeeeeeeeeeeeeeeeeeee";
assert(false);
}

double totalValue = 0;
for (size_t x = 0; x < total.size(); x++)
totalValue += total[x];

return totalValue;
}

double WhatsTheKPlet(const string source, int &i) {
int n = i;
int count = 0;
while (true) {
if (source[n] == ')')
count++;

if (source[n] == '(') {
count--;
if (count == 0) {
n--;
break;
}
}
n--;
}

n += 2;
double kPlet = 0;
while (n <= i - 2) {
if (source[n] != '_' && source[n] != '-' && source[n] != '.' && source[n] != ')' && source[n] != '(' && source[n] != '>' && source[n] != '<') {
double noteModifier = FindModifier(source, n);
kPlet += 1.0*noteModifier;
n++;
} else if (source[n] == ')') {
n++;
} else {
while (source[n] == '(')
n++;

if (source[n+1] == '>')
break;

kPlet += kPletBracketsSituation(source, n);

while (source[n] != ')' && source[n] != '>')
n++;
n += 2;
if (source[n+1] == '>')
n += 2;
if (source[n-1] == '<') {
while (source[n] != '>')
n++;
n++;
}
}
}

while (source[i-1] != '<')
i++;

return kPlet;
}

void CalculateNplet(int &i, const string source, vector &setOfNotes, vector &notes) {
i += 2;

double kPlet = WhatsTheKPlet(source, i);

string number = "      ";
double divideBy;
int n = 0;
while (source[i+n] != '>') {
number[n] = source[i+n];
n++;
}
i += n;

divideBy = atof(number.c_str());
double multiplier = divideBy/kPlet;

for (size_t j = 0; j < setOfNotes.size(); j++) {
setOfNotes[j].value *= multiplier;
notes.push_back(setOfNotes[j]);
}

return;
}

void CalculateCurrentNote(noteT &currNote, const string source, int i, int &increment) {
CalculateNoteValue(source, currNote, i, increment);

if (source[i] == '0')
currNote.rest = true;
else
currNote.rest = false;
return;
}

void WithinBrackets(const string source, int &i, vector &notes) {
vector setOfNotes, within;
i++; // To get past '(' char
while (source[i] != ')') {
if (source[i] == '(') {
WithinBrackets(source, i, within);
i++;

for (size_t j = 0; j < within.size(); j++)
setOfNotes.push_back(within[j]);

within.clear();
}

if (source[i] == ')')
break;

noteT currNote;
int increment = 1;
currNote.value = 1.0 / timeSig;
CalculateCurrentNote(currNote, source, i, increment);
i += increment + 1;

setOfNotes.push_back(currNote);
}

if (source[i+1] == '_' || source[i+1] == '-' || source[i] == '.') {
int increment;
for (size_t j = 0; j < setOfNotes.size(); j++) { // Slightly inefficient but more readable and no copied code.
increment = 1;
CalculateNoteValue(source, setOfNotes[j], i, increment);
notes.push_back(setOfNotes[j]);
}
i += increment;
} else if (source[i+1] == '<') {
int dummy = i;
CalculateNplet(dummy, source, setOfNotes, notes);
i = dummy;
} else {
cout << "\nBad input: char \'" << source.substr(0, i+1) << "\' after \')\'.\nSIGABRT time! Wheeeeeeeeeeeeeeeeeeee";
assert(false);
}
}

bool BadBrackets(string &source) {
int openSmooth = 0;
int openAlligator = 0;

for (size_t i = 0; i < source.length(); i++) {
if (source[i] == ')')
openSmooth--;
if (source[i] == '(')
openSmooth++;
if (source[i] == '<')
openAlligator++;
if (source[i] == '>')
openAlligator--;
}
return  openSmooth != 0 && openAlligator != 0;
}

void VectorizeNotes(vector &notes, const string source) {
for (size_t i = 0; i < source.length(); i++) {
if (source[i] == ' ')
return;

if (source[i] != '(') {
noteT currNote;
int increment = 1;
currNote.value = 1.0 / timeSig;
CalculateCurrentNote(currNote, source, i, increment);
i += increment;
notes.push_back(currNote);
} else {
int dummy = i;
WithinBrackets(source, dummy, notes);
i = dummy;
}
}
return;
}

bool VectorCount(const vector &v, double n) {
for (size_t i = 0; i < v.size(); i++)
if (v[i] == n)
return true;
return false;
}

void RemoveSpaces(string &hand) {
while (hand.find(" ") != -1) {
for (size_t i = 0; i < hand.length(); i++) {
if (hand[i] == ' ') {
string left = hand.substr(0, i);
string right = hand.substr(i+1, hand.size() - 1);
hand = left + right;
}
}
}
return;
}

void ReadHand(vector &notes, string &hand, const string whichHand) {
cout << "Enter notes for the " << whichHand << " hand: ";
while (true) {
hand = GetLine();
if (hand[hand.length()] != ' ')
hand += " ";

if (BadBrackets(hand))
cout << "Unbalanced brackets! Try again: ";
else
break;
}

RemoveSpaces(hand);
VectorizeNotes(notes, hand);
return;
}

int FindNNotes(vector notes) {
vector values;
// Get rid of duplicate note values
for (size_t i = 0; i < notes.size(); i++) {
double value = 1.0/notes[i].value;
if (!VectorCount(values, value)) {
values.push_back(value);
}

}

// Find LCM of all the note values
for (size_t i = 0; i < values.size() - 1; i++) {
values[i] = LCM(values[i], values[i+1]);
values.erase(values.begin() + i +1);
i--;
}

return values[0];
}

void DoHand(vector &notes, string &hand) {
hand = "";
for (int i = 0; i < nSubBeats; i++)
hand += "-";

int numNotes = notes.size();

notes[0].position = 0;
for (size_t i = 1; i < numNotes; i++) {
notes[i].position = (notes[i-1].position + notes[i-1].value);
}

double sum = notes[numNotes-1].position + notes[numNotes-1].value;
if (!CloseEnough(sum)) {
cout << "\nOK, so, you didn't enter a full bar of notes. \nOr more than one. Try compiling and running again!\n";
cout << "SIGABRT time!\n";
assert(false);
return;
}

for (size_t i = 0; i < numNotes; i++) {
if (notes[i].rest == false) {
int index = Round(notes[i].position*hand.length());
hand[index] = 'o';
} else {
hand[notes[i].position*hand.length()] = '_';
int howManyMore = notes[i].value*hand.length();
for (int j = 1; j < howManyMore; j++) {
hand[notes[i].position*hand.length()+j] = '_';
}
}
}

return;
}

void Welcome() {
cout << "Hiya! Enter rhythms for both hands to see how they fit together.\n";
cout << "First, some formatting and syntax info: \n";
cout << "• Notes are assumed to be one beat long\n";
cout << "• Select sets of notes with ( and ). For example: (oooo)\n";
cout << "• Lengthen or shorten a note or set of notes with the following operators:\n '-'(+1 beat)\n '_'(/2)\n '.'(*1.5)\n\n";
cout << "• Make n-plets with alligator mouths; use them after a ')' char. An n-plet is n notes in the time of however many.\n";
cout << "• For example: (ooooo)<2> is ooooo in the time of two beats. That is, five notes (ooooo) in the time of two notes of one beat each.\n";
cout << "• You don't need to mark the notes within an n-plet as sixteenth notes or whatever -- just without any modifications will be fine.\n";
cout << "• If notes within a n-plet are of different lengths, be sure to mark the first number within the alligator mouths as the number of beats within the n-plet.\n";
cout << "• Finally, pretty much any character can signify a note, except for '_', '-', '.', '<', '>', '(', ')' and '0'. (0 signifies a rest).\n";
cout << "Here's an example (In 3-4 time): \nRH is (ooo_)<2>o, LH is ooo. Generates the following: \no---o---o-o----\no----o----o----\n\n";
return;
}

void Simpler() {
cout << "Enter the number of notes played in the hand that has more notes to play: ";
int more = GetInteger();
cout << "Enter the number of notes played in the hand that has fewer to play: ";
int fewer = GetInteger();

string moreH = "";
int totalLength = more * fewer;
for (int i = 0; i < totalLength; i++)
moreH+= "-";

string fewerH = moreH;

for (size_t i = 0; i < fewer; i++)
fewerH[i*more] = 'o';

for (size_t i = 0; i < more; i++)
moreH[i*fewer] = 'o';

cout << moreH << endl << fewerH << endl;
return;
}

int main (int argc, char * const argv[]) {
while (true) {
cout << "Would you like to enter rhythms for both hands (enter '1') or uniform rhythms (enter '2')? ";
string answer = GetLine();
if (answer[0] == '2') {
Simpler();
return 0;
} else if (answer[0] == '1')
break;
}

vector RHnotes, LHnotes;
Welcome();

while (true) {
cout << "\nEnter the number on the top part of the time signature: ";
timeSig = GetInteger();

ReadHand(RHnotes, RH, "right");
ReadHand(LHnotes, LH, "left");

cout << "RH is " << RH << endl;
cout << "LH is " << LH << endl;

double nR = FindNNotes(RHnotes);
double nL = FindNNotes(LHnotes);
nSubBeats = LCM(nR, nL);

DoHand(RHnotes, RH);
DoHand(LHnotes, LH);

cout << "The minimal number of beats to represent the right hand is " << nR << ".\n";
cout << "The minimal number of beats to represent the left hand is " << nL << ".\n";
cout << "The minimum total number of sub-beats is " << nSubBeats << ".\n";
PrintfBeat(RH);
cout << RH << endl;
cout << LH << endl;

cout << "Would you like to do another one? ";
string response = GetLine();
if (response[0] == 'n' || response[0] == 'N')
break;
}
return 0;
}