Dart 04: Thuật toán Reverse bits

const INT_LENGTH = 4;
void main() {
  print("Reverse Whole Binary");
  int x = 8;
  print(decimalToBitString(x, true));
  print(decimalToBitString(reverseBit(x), true));
}

String decimalToBitString(int x, bool paddingZero) {
  String bitString = "";
  if (paddingZero) {
    for (var i = 0; i < INT_LENGTH; i++) {
      bitString = ((x & 1 == 1) ? "1" : "0") + bitString;
      x = x >> 1;
    }
  } else {
    while (x > 0) {
      bitString = ((x & 1 == 1) ? "1" : "0") + bitString;
      x = x >> 1;
    }
  }
  return bitString;
}

int reverseBit(int x) {
  int r = 0;
  for (var i = 0; i < INT_LENGTH; i++) {
    r = r << 1;
    r = r | (x & 1);
    x = x >> 1;
  }
  return r;
}