A very scary for loop

fast-pow/pow.cpp

@@ -0,0 +1,9 @@
+#include <iostream>
+#include <numbers>
+
+auto pw(auto b,int e){auto r=b;for(--e<<=1;e>>=1;r*=(e&1)*b,b*=b);return r;}
+
+int main() {
+    std::cout << pw(2, 4) << std::endl;
+    std::cout << pw(std::numbers::e, 2) << std::endl;
+}