4x4 keypad matrix for Arduino

keypadmatrix

int getKey() {
  int A = 2;
  while (A <= 5) {
    pinMode(A, OUTPUT);
    digitalWrite(A, HIGH);
    int B = 6;
    while (B <= 9) {
      pinMode(B, OUTPUT);
      pinMode(B, INPUT);
      if (digitalRead(B) == HIGH) {
        return (A - 2) * 4 + (B - 5);
      }
    }
    digitalWrite(A, LOW);
    A = A + 1;
  }
  return 0;
}