#include <LiquidCrystal.h>
#include <Keypad.h>
const byte KEYPAD_ROWS = 4;
const byte KEYPAD_COLS = 4;
byte rowPins[KEYPAD_ROWS] = {5, 4, 3, 2};
byte colPins[KEYPAD_COLS] = {A3, A2, A1, A0};
char keys[KEYPAD_ROWS][KEYPAD_COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, KEYPAD_ROWS, KEYPAD_COLS);

LiquidCrystal lcd(12, 11, 10, 9, 8, 7);

void setup() {
  Serial.begin(115200);
  lcd.begin(16, 2);
  lcd.setCursor(0, 0); 
}
void loop() {
  int n;
  int  i,j,t;
  double *data;
  char key ;
  boolean valid = false; 

  while(!n){
    lcd.setCursor(0,0);
    lcd.print("Total # to sort:");
    key = keypad.getKey();
    
    if (key){
     if(checkIfNum(key) & key != '0'){
      n = String(key).toInt();
      data = (double *)calloc(n, sizeof(double));;
      lcd.clear();
     }
     else{
      valid_num();
      }
    }
  }

  for (int i = 0; i < n; ++i) {
    valid = false;
  while(!valid){
    lcd.setCursor(0,0);
    lcd.print(" # input ");
    lcd.print(i+1);
    lcd.setCursor(0,1);
    lcd.print("   out of ");
    lcd.print(n);
    key = keypad.getKey();
    if(key){
      if(checkIfNum(key)){
      int ascii = key;
      data[i] = ascii -48;
      valid = true;
      }
      else{
      valid_num();
      }
    }
 
  }
  lcd.clear();
  }
  
  for (int i = 0; i < n; ++i) {
   for (j = 0; j <= i; ++j)
      {
         if (*(data +i)  <* (data + j))
         {
            t = *(data+i);
            *(data+i) =  *(data+j);
            *(data+j) = t;
         }
      }
  }

  lcd.setCursor(0,0);
  lcd.print(" Ascending order: ");
  delay(1000);
  lcd.clear();
  lcd.setCursor(0,0);
  for (i = 0; i < n; ++i)
  lcd.print(data[i]);
  free(data);
  delay(5000);
  lcd.clear();
}

boolean checkIfNum(char input_char){
  if(input_char == 'A' or input_char == 'B' or input_char == 'C' or input_char == 'D' or input_char == '*' or input_char == '#'){
    return false;
  }
  else{
    return true;
  }
}

void valid_num(){
lcd.clear();
lcd.setCursor(0,0);
lcd.print(" Invalid Number!");
delay(2000);
lcd.clear();
}