diff --git a/week1.java b/week1.java index 5cbb029..30d55e0 100644 --- a/week1.java +++ b/week1.java @@ -1,10 +1,12 @@ import java.util.Calendar; +import java.util.Scanner; import java.util.concurrent.ThreadLocalRandom; class runLabs { public static void main(String[] args) { new Lab4(); new Lab5(); + new Lab6(); } } @@ -13,11 +15,20 @@ class Section { public Section(int s) { this._sectionNumber = s; + this.printSection(); } public int getSection() { return _sectionNumber; } + + public void printSection() { + String title = String.format("Starting section %s", this._sectionNumber); + + System.out.println("-".repeat(title.length())); + System.out.println(String.format("%s", title)); + System.out.println("-".repeat(title.length())); + } } class Lab { @@ -200,9 +211,132 @@ class Lab4 extends Lab { } } +/** + * Keyboard input + */ class Lab5 extends Lab { public Lab5() { super(5); - System.out.println(String.format("hi")); + new five1(); + } + + class five1 extends Section { + /** + * We will now look at how we can get user input from the keyboard. We will + * gloss over some + * of the details here, but give you just the information you need to start + * getting input and + * processing it. + */ + public five1() { + super(1); + System.out.println(String.format("TBC")); + // Scanner keyboard = new Scanner(System.in); + // System.out.println("Please enter your name, followed by the return key?"); + // String userEntry = keyboard.nextLine(); + // System.out.println("Hello " + userEntry); + // System.out.println(String.format("%s", keyboard)); + } + } +} + +/** + * Loops + */ +class Lab6 extends Lab { + public Lab6() { + super(6); + new six1(); + System.out.println(String.format("%n")); + new six3(); + new six5(); + } + + /** + * Times tables + */ + class six1 extends Section { + public six1() { + super(1); + int testNum = 6; + System.out.println(String.format("Times table for %d:", testNum)); + writeTimesTable(7); + } + } + + class six3 extends Section { + public six3() { + super(3); + int testNum = 13; // statistically the most prime of all numbers + System.out.println(String.format("Testing primes...")); + System.out.println(String.format("%d prime? %s", testNum, isPrime(testNum))); + System.out.println(String.format("%d prime? %s", 23, isPrime(23))); + System.out.println(String.format("%d prime? %s", 27, isPrime(27))); + System.out.println(String.format("%d prime? %s", 28, isPrime(28))); + System.out.println(String.format("%d prime? %s", 299, isPrime(299))); + System.out.println(String.format("Generating primes...")); + generatePrimes(1024); + System.out.println(String.format("Done!%n")); + } + } + + class six5 extends Section { + public six5() { + super(5); + System.out.println(String.format("TODO / NOT IMPLEMENTED until we get stdin working")); + } + } + + public void writeTimesTable(int num, int limit) { + for (int i = 0; i < (limit + 1); i++) { + System.out.printf("%d\t", num * i); + } + } + + public void writeTimesTable(int num) { + int DEFAULT_LIMIT = 10; + writeTimesTable(num, DEFAULT_LIMIT); + } + + public void generatePrimes(int upperLimit) { + // handle 2 as a special case + System.out.println(String.format("2")); + // for (int i = 3; i <= upperLimit; i += 2) { + for (int i = 2; i <= upperLimit; i++) { + // TODO: figure out smarter way of doing this, I'm sure primes must be at least 6 apart... + // Something about 2n ± 1 ? + // seive of Erasthotenes ..? + if (isPrime(i)) { + System.out.printf("%d\t", i); + } + } + } + + /** + * But is it prime? + * @param num Integer to test for primality + * @return if it's prime + */ + public boolean isPrime(int num) { + boolean DEBUG = false; + if ((num == 2) || (num == 1)) { + return true; + } + if (num % 2 == 0){ + return false; + } else { + int divisor = 3; + double numSquareRoot = Math.sqrt((double)num); + while (divisor <= numSquareRoot) { + if (num % divisor == 0) { + return false; + } + divisor += 2; + if (DEBUG) { + System.out.printf("%d\t", divisor); + } + } + return true; + } } }