Morse Code with 18-Pin 16-Segment LED Display

#include <Arduino.h>

int i = -1, j, port, N = -1, idx, AN = 0;
int rst, dot, das;
String code = "";

String Morse[36] = {
  {".----"}, //1
  {"..---"}, //2
  {"...--"}, //3
  {"....-"}, //4
  {"....."}, //5
  {"-...."}, //6
  {"--..."}, //7
  {"---.."}, //8
  {"----."}, //9
  {"----*"}, //0
  {".-***"}, //a
  {"-...*"}, //b
  {"-.-.*"}, //c
  {"-..**"}, //d
  {".****"}, //e
  {"..-.*"}, //f
  {"--.**"}, //g
  {"....*"}, //h
  {"..***"}, //i
  {".---*"}, //j
  {"-.-**"}, //k
  {".-..*"}, //l
  {"--***"}, //m
  {"-.***"}, //n
  {"---**"}, //o
  {".--.*"}, //p
  {"--.-*"}, //q
  {".-.**"}, //r
  {"...**"}, //s
  {"-****"}, //t
  {"..-**"}, //u
  {"...-*"}, //v
  {".--**"}, //w
  {"-..-*"}, //x
  {"-.--*"}, //y
  {"--..*"}, //z
};

boolean SEG16[36][18] = {
  {0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, //1
  {1, 0, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0}, //2
  {1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0}, //3
  {0, 0, 1, 1, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0}, //4
  {1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0}, //5
  {1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0}, //6
  {1, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, //7
  {1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0}, //8
  {1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0}, //9
  {1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0}, //0
  {1, 0, 1, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0}, //A
  {1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1}, //B
  {1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 1, 1}, //C
  {1, 0, 1, 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1}, //D
  {1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1}, //E
  {1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0}, //F
  {1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 0, 1, 1}, //G
  {0, 0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0}, //H
  {1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1}, //I
  {1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0, 1, 1}, //J
  {0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0}, //K
  {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1}, //L
  {0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0}, //M
  {0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0}, //N
  {1, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 1, 1}, //O
  {1, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0}, //P
  {1, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 1, 1}, //Q
  {1, 1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0}, //R
  {1, 0, 0, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 1}, //S
  {1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0}, //T
  {0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1}, //U
  {0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0}, //V
  {0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0}, //W
  {0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0}, //X
  {0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0}, //Y
  {1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 1}, //Z
};

void setup() {
  Serial.begin(9600);

  pinMode(7, INPUT);
  pinMode(8, INPUT);
  pinMode(9, INPUT);

  for (j = 22; j < 40; j++) {
    pinMode(j, OUTPUT);
  }
}

void loop() {
  delay(1000);

  das = digitalRead(7);
  dot = digitalRead(8);
  rst = digitalRead(9);

  if (rst == 1 || N > 4) {
    for (i = 0; i < 36; i++) {
      idx = Morse[i].indexOf("*");
      //idx = code.length();
      if (code.compareTo(Morse[i].substring(0, idx)) == 0) {
        AN = i;
        Serial.println(AN);
        break;
      }
    }
    N = -1;
    code = "";
  }
  
  if (dot == 1) {
    N = N + 1;
    code = String(code + ".");
  }
  if (das == 1) {
    N = N + 1;
    code = String(code + "-");
  }

  Serial.print(code);
  Serial.print("\n");

  //  AN = (AN + 1) % 36;
    for (j = 0; j < 18; j++) {
      port = 22 + j;
      if (SEG16[AN][j] == 0) {
        digitalWrite(port, HIGH);
      }
      else {
        digitalWrite(port, LOW);
      }
    }
}