pattern.dart

// Constructing the string to print multiple times
  String plus = "";
  String bars = "";

  // Plus sign string
  for (int i = 0; i < cols ; i ++) {
    plus += "+-";
  }
  plus += "+";

  // Bar sign string
  for (int i = 0; i < cols ; i ++) {
    bars += "|.";
  }
  bars += "|";

  // Printing rest of the punch card
  for (int i = 0; i < rows ; i ++) {
    print(plus);
    if (i == rows - 1) {
      continue;
    } else {
      print(bars);
    }
  }