Data commit

Task/Modular-exponentiation/ALGOL-68/modular-exponentiation.alg

@@ -0,0 +1,23 @@
+BEGIN
+   PR precision=1000 PR
+   MODE LLI = LONG LONG INT;	CO For brevity CO
+   PROC mod power = (LLI base, exponent, modulus) LLI :
+   BEGIN
+      LLI result := 1, b := base, e := exponent;
+      IF exponent < 0
+      THEN
+	 put (stand error, (("Negative exponent", exponent, newline)))
+      ELSE
+	 WHILE e > 0
+	 DO
+	    (ODD e | result := (result * b) MOD modulus);
+	    e OVERAB 2; b := (b * b) MOD modulus
+	 OD
+      FI;
+      result
+   END;
+   LLI a = 2988348162058574136915891421498819466320163312926952423791023078876139;
+   LLI b = 2351399303373464486466122544523690094744975233415544072992656881240319;
+   LLI m = 10000000000000000000000000000000000000000;
+   printf (($"Last 40 digits = ", 40dl$, mod power (a, b, m)))
+END