zmodn

commit 32cce8fe6a4b35d24d6a63b3226daee2a2753684
parent 7e705a3342bc36f9f02b4e8e0050bc5842a62f9b
Author: Sebastiano Tronto <sebastiano@tronto.net>
Date:   Sat, 21 Dec 2024 17:38:19 +0100

Added power operator

Diffstat:
M
test
 | 
8
++++++++
M
zmodn.h
 | 
7
+++++++

2 files changed, 15 insertions(+), 0 deletions(-)
diff --git a/test b/test
@@ -133,6 +133,14 @@ public:
 		assert_equal(n.toint(), 2);
 	}
 },
+{
+	.name = "2^12 mod 154",
+	.f = []() {
+		Zmod<154> b = 2;
+		auto p = b ^ 12;
+		assert_equal(p, 92);
+	}
+},
 };
 
 int main() {
diff --git a/zmodn.h b/zmodn.h
@@ -25,10 +25,17 @@ public:
 	Zmod operator+(const Zmod& z) const { return value + z.value; }
 	Zmod operator-(const Zmod& z) const { return value - z.value; }
 	Zmod operator*(const Zmod& z) const { return value * z.value; }
+
 	Zmod operator+=(const Zmod& z) { return (*this) = value + z.value; }
 	Zmod operator-=(const Zmod& z) { return (*this) = value - z.value; }
 	Zmod operator*=(const Zmod& z) { return (*this) = value * z.value; }
 
+	Zmod operator^(decltype(N) z) const {
+		if (z == 0) return 1;
+		if (z % 2 == 0) return (((*this) * (*this)) ^ (z/2));
+		return (*this) * ((*this) ^ (z-1));
+	}
+
 	bool operator==(const Zmod& z) const { return value == z.value; }
 	bool operator!=(const Zmod& z) const { return value != z.value; }