1 files changed, 13 insertions, 0 deletions

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";