Strong and weak primes: Difference between revisions

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@@ Line 1,830: / Line 1,830: @@
 strong primes and 37780 weak primes below 1000000.
 strong primes and 321750 weak primes below 10000000.
+</pre>
+=={{header|Rust}}==
+<lang rust>fn is_prime(n: i32) -> bool {
+	for i in 2..n {
+		if i * i > n {
+			return true;
+		}
+		if n % i == 0 {
+			return false;
+		}
+	}
+	n > 1
+}
+fn next_prime(n: i32) -> i32 {
+	for i in (n+1).. {
+		if is_prime(i) {
+			return i;
+		}
+	}
+}
+fn main() {
+	let mut n = 0;
+	let mut prime_q = 5;
+	let mut prime_p = 3;
+	let mut prime_o = 2;
+	print!("First 36 strong primes: ");
+	while n < 36 {
+		if prime_p > (prime_o + prime_q) / 2 {
+			print!("{} ",prime_p);
+			n += 1;
+		}
+		prime_o = prime_p;
+		prime_p = prime_q;
+		prime_q = next_prime(prime_q);
+	}
+	println!("");
+	while prime_p < 1000000 {
+		if prime_p > (prime_o + prime_q) / 2 {
+			n += 1;
+		}
+		prime_o = prime_p;
+		prime_p = prime_q;
+		prime_q = next_prime(prime_q);
+	}
+	println!("strong primes below 1,000,000: {}", n);
+	while prime_p < 10000000 {
+		if prime_p > (prime_o + prime_q) / 2 {
+			n += 1;
+		}
+		prime_o = prime_p;
+		prime_p = prime_q;
+		prime_q = next_prime(prime_q);
+	}
+	println!("strong primes below 10,000,000: {}", n);
+	n = 0;
+	prime_q = 5;
+	prime_p = 3;
+	prime_o = 2;
+	print!("First 36 weak primes: ");
+	while n < 36 {
+		if prime_p < (prime_o + prime_q) / 2 {
+			print!("{} ",prime_p);
+			n += 1;
+		}
+		prime_o = prime_p;
+		prime_p = prime_q;
+		prime_q = next_prime(prime_q);
+	}
+	println!("");
+	while prime_p < 1000000 {
+		if prime_p < (prime_o + prime_q) / 2 {
+			n += 1;
+		}
+		prime_o = prime_p;
+		prime_p = prime_q;
+		prime_q = next_prime(prime_q);
+	}
+	println!("weak primes below 1,000,000: {}", n);
+	while prime_p < 10000000 {
+		if prime_p < (prime_o + prime_q) / 2 {
+			n += 1;
+		}
+		prime_o = prime_p;
+		prime_p = prime_q;
+		prime_q = next_prime(prime_q);
+	}
+	println!("weak primes below 10,000,000: {}", n);
+}</lang>
+<pre>
+First 36 strong primes: 11 17 29 37 41 59 67 71 79 97 101 107 127 137 149 163 179 191 197 223 227 239 251 269 277 281 307 311 331 347 367 379 397 419 431 439
+strong primes below 1,000,000: 37723
+strong primes below 10,000,000: 320991
+First 36 weak primes: 7 13 19 23 31 43 47 61 73 83 89 103 109 113 131 139 151 167 181 193 199 229 233 241 271 283 293 313 317 337 349 353 359 383 389 401
+weak primes below 1,000,000: 37779
+weak primes below 10,000,000: 321749
 </pre>