08 Individual relay drive by (TPIC6B595)

Projects Programming
4

I am not good in coding but I get the result with below code. Can anyone explain that.
because when I use same function in state change example is stop working.

const int latchPin = 10;
const int clockPin = 9;
const int dataPin = 12;
const int OE        = 11;

int Btn1 = A0;  //button 1 connected to pin 1
int Btn2 = 5;  //button 2 connected to pin 2
int Btn3 = 6;  //button 3 connected to pin 3
int Btn4 = 7;  //button 4 connected to pin 4
int Btn5 = A4;  //button 5 connected to pin 5
int Btn6 = A3;  //button 6 connected to pin 6
int Btn7 = A2;  //button 7 connected to pin 7
int Btn8 = A1;  //button 8 connected to pin 8


int buttonstate1 = 0;    //state button 1
int buttonstate2 = 0;    //state button 2
int buttonstate3 = 0;    //state button 3
int buttonstate4 = 0;    //state button 4
int buttonstate5 = 0;    //state button 5
int buttonstate6 = 0;    //state button 6
int buttonstate7 = 0;    //state button 7
int buttonstate8 = 0;    //state button 8

int Led1 = 0;  //Light1 on/off
int Led2 = 0;  //Light2 on/off
int Led3 = 0;  //Light3 on/off
int Led4 = 0;  //Light4 on/off
int Led5 = 0;  //Light5 on/off
int Led6 = 0;  //Light6 on/off
int Led7 = 0;  //Light7 on/off
int Led8 = 0;  //Light8 on/off

byte leds = 0;

void setup()
{
  pinMode(OE, OUTPUT);
  digitalWrite(OE, LOW);
  pinMode(Btn1, INPUT_PULLUP);
  pinMode(Btn2, INPUT_PULLUP);
  pinMode(Btn3, INPUT_PULLUP);
  pinMode(Btn4, INPUT_PULLUP);
  pinMode(Btn5, INPUT_PULLUP);
  pinMode(Btn6, INPUT_PULLUP);
  pinMode(Btn7, INPUT_PULLUP);
  pinMode(Btn8, INPUT_PULLUP);
  pinMode(latchPin, OUTPUT);
  pinMode(dataPin, OUTPUT);
  pinMode(clockPin, OUTPUT);

}

void loop()
{
  buttonstate1 = digitalRead(Btn1);
  buttonstate2 = digitalRead(Btn2);
  buttonstate3 = digitalRead(Btn3);
  buttonstate4 = digitalRead(Btn4);
  buttonstate5 = digitalRead(Btn5);
  buttonstate6 = digitalRead(Btn6);
  buttonstate7 = digitalRead(Btn7);
  buttonstate8 = digitalRead(Btn8);

  if (buttonstate1 == LOW && Led1 == 0)
  {
    leds ^= B00000001;
    updateShiftRegister();
     delay(200);
  }

  if (buttonstate2 == LOW && Led2 == 0)
  {
    leds ^= B00000010;
    updateShiftRegister();
     delay(200);
  }

  if (buttonstate3 == LOW && Led3 == 0)
  {
    leds ^= B00000100;
    updateShiftRegister();
     delay(200);
  }

  if (buttonstate4 == LOW && Led4 == 0)
  {
    leds ^= B00001000;
    updateShiftRegister();
     delay(200);
  }

  if (buttonstate5 == LOW && Led5 == 0)
  {
    leds ^= B00010000;
    updateShiftRegister();
     delay(200);
  }

  if (buttonstate6 == LOW && Led6 == 0)
  {
    leds ^= B00100000;
    updateShiftRegister();
     delay(200);
  }

  if (buttonstate7 == LOW && Led7 == 0)
  {
    leds ^= B01000000;
    updateShiftRegister();
     delay(200);
  }

  if (buttonstate8 == LOW && Led8 == 0)
  {
    leds ^= B10000000;
    updateShiftRegister();
     delay(200);
  }
}

void updateShiftRegister()
{
  digitalWrite(latchPin, LOW);
  shiftOut(dataPin, clockPin, MSBFIRST, leds);
  digitalWrite(latchPin, HIGH);
}