AP Compsci A Summer Work - CodingBat

notString.java

public String notString(String str) {
  // If the arg starts with not... (https://howtodoinjava.com/java/string/java-string-startswith-example/)
  if (str.startsWith("not")) {
    return str;
  // Otherwise...
  } else {
    return "not " + str;
  }
}

sleepIn.java

public boolean sleepIn(boolean weekday, boolean vacation) {
  // If it's not a weekday, OR it's vacation...
  if (!weekday || vacation) {
    return true;
  // Otherwise
  } else {
    return false;
  }
}

startHi.java

public boolean startHi(String str) {
  // if arg starts with hi...
  if (str.startsWith("hi")) {
    return true;
  // Otherwise...
  } else {
    return false;
  }
}