From 3ab61ce2bd4549da4567040a12f6f471fc9597cb Mon Sep 17 00:00:00 2001
From: Scott Baker <scott@perturb.org>
Date: Thu, 14 Mar 2019 15:18:09 -0700
Subject: [PATCH] Add a new example

---
 examples/Primes/Primes.ino | 86 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 86 insertions(+)
 create mode 100644 examples/Primes/Primes.ino

diff --git a/examples/Primes/Primes.ino b/examples/Primes/Primes.ino
new file mode 100644
index 0000000..00b2431
--- /dev/null
+++ b/examples/Primes/Primes.ino
@@ -0,0 +1,86 @@
+const char* host     = "ESP32-OTA"; // Used for MDNS resolution
+const char* ssid     = "ssid";
+const char* password = "password";
+
+#include <WebOTA.h>
+WebServer OTAServer(8080);
+
+long start       = 0;
+long max_seconds = 30;
+long i           = 2; // Start at 2
+long found       = 0; // Number of primtes we've found
+int LED_PIN      = 16;
+
+void setup() {
+	Serial.begin(115200);
+
+	while (!Serial) { }
+
+	pinMode(LED_PIN, OUTPUT);
+	start = millis();
+
+	init_wifi(ssid, password, host);
+	init_web_ota(&OTAServer);
+}
+
+void loop() {
+	digitalWrite(LED_PIN, HIGH);
+	bool prime = is_prime(i); // Check if the number we're on is prime
+
+	if (prime) {
+		Serial.print(i);
+		Serial.println(" is prime ");
+
+		found++;
+	}
+
+	int running_seconds = (millis() - start) / 1000;
+
+	if (max_seconds > 0 && (running_seconds >= max_seconds)) {
+		Serial.print("Found ");
+		Serial.print(found);
+		Serial.print(" primes in ");
+		Serial.print(max_seconds);
+		Serial.println(" seconds");
+		digitalWrite(LED_PIN, LOW);
+
+		webota_delay(15 * 1000, &OTAServer);
+
+		i     = 2;
+		found = 0;
+		start = millis();
+	}
+
+	i++;
+
+	OTAServer.handleClient();
+}
+
+bool is_prime(long num) {
+	// Only have to check for divisible for the sqrt(number)
+	int upper = sqrt(num);
+
+	// Check if the number is evenly divisible (start at 2 going up)
+	for (long cnum = 2; cnum <= upper; cnum++) {
+		long mod = num % cnum; // Remainder
+
+		if (mod == 0) {
+			return false;
+		} // If the remainer is 0 it's evenly divisible
+	}
+
+	return true; // If you get this far it's prime
+}
+
+
+
+bool is_prime2(long number) {
+	if (number < 2) return false;
+	if (number == 2) return true;
+	if (number % 2 == 0) return false;
+	for(int i=3; (i*i)<=number; i+=2){
+		if (number % i == 0 ) return false;
+	}
+
+	return true;
+}