From d16656919753438a57a32f9ad6ba972c25d66b11 Mon Sep 17 00:00:00 2001
From: Sebastiano Tronto <sebastiano@tronto.net>
Date: Sun, 9 Feb 2025 19:38:26 +0100
Subject: Added random number generator for bigint

---
 bigint.h | 13 +++++++++++++
 1 file changed, 13 insertions(+)

(limited to 'bigint.h')

diff --git a/bigint.h b/bigint.h
index 9287fda..096ed9c 100644
--- a/bigint.h
+++ b/bigint.h
@@ -3,6 +3,7 @@
 
 #include <cstdint>
 #include <iostream>
+#include <random>
 #include <string_view>
 
 constexpr uint64_t abs64(int64_t);
@@ -123,6 +124,18 @@ public:
 	constexpr BigInt operator/=(const BigInt& z) { return *this = *this / z; }
 	constexpr BigInt operator%=(const BigInt& z) { return *this = *this % z; }
 
+	static BigInt random(BigInt r) {
+		std::random_device rd;
+		std::default_random_engine rng(rd());
+		std::uniform_int_distribution<int> distribution(0, M-1);
+
+		BigInt ret;
+		for (uint64_t i = 0; i < D; i++)
+			ret.digits[i] = distribution(rng);
+
+		return ret % r;
+	}
+
 	friend std::ostream& operator<<(std::ostream& os, const BigInt<N, E>& z) {
 		if (z == 0) {
 			os << "0";
-- 
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