need help adding debounce to my code

Using Arduino Programming Questions
11

Edit: Your code can be greatly simplified with the correct use of arrays, but try this. All I did was modify the example code.

/* 
 Debounce
 This example code is in the public domain.
 http://www.arduino.cc/en/Tutorial/Debounce
 */

// constants won't change. They're used here to 
// set pin numbers:
const int buttonPin[] = {2,3,4,5};
const int ledPins[] =  {8,9,10,11};      // the number of the LED pin

int MAX_PINS = 4;
int i = 0;
int counter=0;
int reading[4];

//byte ledState = HIGH;

int buttonState[4];             // the current reading from the input pin
int lastButtonState[] = {LOW,LOW,LOW,LOW};   // the previous reading from the input pin
long lastDebounceTime[] = {0,0,0,0};  // the last time the output pin was toggled

long debounceDelay = 50;    // the debounce time; increase if the output flickers

void setup() {
  for(i = 0; i <= MAX_PINS; i++){
    pinMode(buttonPin[i], INPUT);
    pinMode(ledPins[i], OUTPUT);
  }
}

void loop() {
  // read the state of the switch into a local variable:
  for(counter = 0; counter <= MAX_PINS; i++)
  {
    reading[counter] = digitalRead(buttonPin[counter]);
    if (reading[counter] != lastButtonState[counter]) {
    lastDebounceTime[counter] = millis();
    } 

    if ((millis() - lastDebounceTime[counter]) > debounceDelay) {
      buttonState[counter] = reading[counter];
    }

    digitalWrite(ledPins[counter], buttonState[counter]);
    lastButtonState[counter] = reading[counter];
  }
}