classic recursion (watch this, it blows stack) (defn exp [x n] (if (zero? n) 1 (* x (exp x (dec n))))) tail recursion (defn exp [x n] (loop [acc 1 n n] (if (zero? n) acc (recur (* x acc) (dec n))))) functional (defn exp [x n] (reduce * (repeat n x))) sneaky (also blows … Read more
Exponentiation by squaring. int ipow(int base, int exp) { int result = 1; for (;;) { if (exp & 1) result *= base; exp >>= 1; if (!exp) break; base *= base; } return result; } This is the standard method for doing modular exponentiation for huge numbers in asymmetric cryptography.
The ^ operator in Java ^ in Java is the exclusive-or (“xor”) operator. Let’s take 5^6 as example: (decimal) (binary) 5 = 101 6 = 110 —————— xor 3 = 011 This the truth table for bitwise (JLS 15.22.1) and logical (JLS 15.22.2) xor: ^ | 0 1 ^ | F T –+—– –+—– 0 … Read more