#include <Adafruit_NeoPixel.h>
 
int din = 13;  

int numleds = 16;   

int btnpin = 12;   
 
Adafruit_NeoPixel strip(numleds, din, NEO_GRB + NEO_KHZ800);
 
bool buttonState = false;

bool lastButtonState = false;
 
int colorIndex = 0;

uint32_t colors[] = {

  strip.Color(255, 0, 0),   

  strip.Color(0, 255, 0),   

  strip.Color(0, 0, 255),   

  strip.Color(255, 255, 0), 

  strip.Color(255, 0, 255)  

};
 
void setup() {

  strip.begin();

  strip.show(); 
 
  pinMode(btnpin, INPUT);
 
  Serial.begin(9600);

}
 
void loop() {

  buttonState = digitalRead(btnpin);


  if (buttonState != lastButtonState) {

    if (!buttonState) {

      colorIndex = (colorIndex + 1) % (sizeof(colors) / sizeof(colors[0]));

      setColor(colors[colorIndex]);

      Serial.print("Color changed to index ");

      Serial.println(colorIndex);

    }

    lastButtonState = buttonState;

  }

}
 
void setColor(uint32_t color) {

  for (int i = 0; i < numleds; i++) {

    strip.setPixelColor(i, color);

  }

  strip.show();

}