From 175721a63b426355274fa9e8063f762020ab8362 Mon Sep 17 00:00:00 2001
From: RossTheRoss <mstrapp@protonmail.com>
Date: Thu, 30 Jan 2020 16:55:04 -0600
Subject: R E A R R A N G E

---
 OLD/csci1913/Java/lab5_strap012.java | 90 ++++++++++++++++++++++++++++++++++++
 1 file changed, 90 insertions(+)
 create mode 100644 OLD/csci1913/Java/lab5_strap012.java

(limited to 'OLD/csci1913/Java/lab5_strap012.java')

diff --git a/OLD/csci1913/Java/lab5_strap012.java b/OLD/csci1913/Java/lab5_strap012.java
new file mode 100644
index 0000000..45a101b
--- /dev/null
+++ b/OLD/csci1913/Java/lab5_strap012.java
@@ -0,0 +1,90 @@
+//
+//  SIEVE. The Sieve of Eratosthenes.
+//
+//    James B. Moen
+//    08 Oct 19
+//
+//  Test the SIEVE class, for 30 points total.
+//
+
+//
+//  Put your code for the class SIEVE here!!!
+//
+class Sieve {
+    private boolean[] numbers;
+    private int realMax;
+  public Sieve(int max){
+    if (max<2) 
+      throw new IllegalArgumentException();
+    numbers = new boolean[max];
+    realMax = (max - 1);
+    for (int i=2; i<max; i+=1) { numbers[i]=true; }
+  }
+  public void findPrimes() {
+    for (int i=2; i<=realMax; i+=1) {
+      //Only look for composite numbers if the number is prime
+      if (numbers[i]) {
+        for (int j=(i*2); j<=realMax; j+=i) {
+          numbers[j]=false;
+        }
+      }
+    //  System.out.println(i);
+    }
+  }
+  public String toString(){
+    String str = "";
+    for (int n = 0; n <= realMax; n += 1) {
+      if (numbers[n]) {
+        str += n; str += " ";
+      }
+    }
+    return str;
+  }
+}
+//  TOSS THE KNEES. Run SIEVE on some examples.
+
+class TossTheKnees
+{
+
+//  MAIN. Find some primes.
+
+  public static void main(String [] args)
+  {
+    Sieve sieve = null;  //  We must initialize SIEVE or Java will cry.
+
+//  5 points. This must print "Sieve size must be at least 2." but without the
+//  quotes.
+
+    try
+    {
+      sieve = new Sieve(0);
+    }
+    catch (IllegalArgumentException oops)
+    {
+      System.out.println("Sieve size must be at least 2.");
+    }
+
+//  5 points. This must print nothing.
+
+    try
+    {
+      sieve = new Sieve(100);
+    }
+    catch (IllegalArgumentException oops)
+    {
+      System.out.println("Sieve size must be at least 2.");
+    }
+
+//  10 points. This must print integers from 2 to 99, separated by blanks.
+
+    System.out.println(sieve);
+
+//  10 points. This must print the prime numbers between 2 and 99, separated by
+//  blanks. They are:
+//
+//  2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97
+
+    sieve.findPrimes();
+    System.out.println(sieve);
+  }
+}
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