#include <TM1637Display.h>
#include <Keypad.h>
#define CLK 2
#define DIO 3
const byte ROWS = 4; //four IOWS
const byte COLS = 4; //three columns

//define the cymbols on the buttons of the keypads
char keypadArray[ROWS][COLS] = {
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};
byte rowPins[ROWS] = {4, 5, 6, 7}; //connect to the row pinouts of the keypad
byte colPins[COLS] = {8, 9, 10,11}; //connect to the column pinouts of the keypad

//initialize an instance of the Keypad class
Keypad myKeypad = Keypad(makeKeymap(keypadArray), rowPins, colPins, ROWS, COLS);
//create a 7. Segment Display library intance
TM1637Display display (CLK, DIO);
int keyNum = 0;
void setup() {
  display.setBrightness(0x0f);
}

void loop() {

  char key = myKeypad.getKey();
  int num = key - '0';
  if (key) {
    Serial.print(key);
    if (key == '*') {
      for (int key=keyNum;key>=0;key--){
        display.showNumberDec(key);}
    } else {
      if(keyNum<=9999){
        keyNum = (keyNum*10) + (int(key)-48);
      }
    }
    if (key == '#'){
      keyNum =0;
       Serial.print(key);
    }
  }
  display.showNumberDec(keyNum,0);
}