How can I stop music with a push button? - if-statement

Question

I would like to know how to stop music with a push button (to stop it exactly at the moment you press the button). Because at the moment my code does what I want(stop the music and turn on a light when I press the press button, but it waits untill the end of the song to stop.
There is my code:
int buttonState = 0;
int speakerOut = 10;
int buttonPin= 7;
int frequency = 500;
int ledPin = 13;
int length = 17; // the number of notes
char notes[] = "gcefgcefgcefgcefga "; // a space represents a rest
//int beats[] = {2,2,1,1,2,2,1,1,2,2,1,1,2,2,1,1};
//int tempo = 250;
int DEBUG = 1;
#define c 3830
#define d 3400
#define e 3038
#define f 2864
#define g 2550
#define a 2272
#define b 2028
#define C 1912
#define R 0
void setup() {
// put your setup code here, to run once:
pinMode(ledPin, OUTPUT);
pinMode(buttonPin,INPUT);
pinMode(speakerOut, OUTPUT);
if (DEBUG) {
Serial.begin(9600); // Set serial out if we want debugging
}
}
// MELODY and TIMING =======================================
// melody[] is an array of notes, accompanied by beats[],
// which sets each note's relative length (higher #, longer note)
int melody[] = { C, b, g, C, b, e, R, C, c, g, a, C };
int beats[] = { 16, 16, 16, 8, 8, 16, 32, 16, 16, 16, 8, 8 };
int MAX_COUNT = sizeof(melody) / 2; // Melody length, for looping.
// Set overall tempo
long tempo = 10000;
// Set length of pause between notes
int pause = 1000;
// Loop variable to increase Rest length
int rest_count = 100; //<-BLETCHEROUS HACK; See NOTES
// Initialize core variables
int tone_ = 0;
int beat = 0;
long duration = 0;
// PLAY TONE ==============================================
// Pulse the speaker to play a tone for a particular duration
void playTone() {
long elapsed_time = 0;
if (tone_ > 0) { // if this isn't a Rest beat, while the tone has
// played less long than 'duration', pulse speaker HIGH and LOW
while (elapsed_time < duration) {
digitalWrite(speakerOut,HIGH);
delayMicroseconds(tone_ / 2);
// DOWN
digitalWrite(speakerOut, LOW);
delayMicroseconds(tone_ / 2);
// Keep track of how long we pulsed
elapsed_time += (tone_);
}
}
else { // Rest beat; loop times delay
for (int j = 0; j < rest_count; j++) { // See NOTE on rest_count
delayMicroseconds(duration);
}
}
}
void loop() {
// put your main code here, to run repeatedly:
buttonState = digitalRead(buttonPin);
if (buttonState==HIGH){
digitalWrite(ledPin, HIGH);
noTone(speakerOut);
}else {
digitalWrite(ledPin, LOW);
digitalWrite(speakerOut,HIGH);
for (int i=0; i<MAX_COUNT; i++) {
tone_ = melody[i];
beat = beats[i];
duration = beat * tempo; // Set up timing
playTone();
// A pause between notes...
delayMicroseconds(pause);
}
}
}

Answer 1

You have 2 options, before playTone() check button and, if pressed, end the for loop.
for (int i=0; i<MAX_COUNT; i++) {
tone_ = melody[i];
beat = beats[i];
duration = beat * tempo; // Set up timing
if (digitalRead(buttonPin)==LOW){
playTone();
} else {
break; //End for loop
}
// A pause between notes...
delayMicroseconds(pause);
}
Or the same but using void loop() as a for loop. A global variable, count between 0 and MAX_COUNT and do the same check. If pressed, count=0; and if not, continue playing the next note. Now, I can't code write this but has no difficult.