RosettaCodeData/Task/Proper-divisors/ALGOL-M/proper-divisors.alg
2023-07-01 13:44:08 -04:00

71 lines
1.5 KiB
Text

BEGIN
% COMPUTE P MOD Q %
INTEGER FUNCTION MOD (P, Q);
INTEGER P, Q;
BEGIN
MOD := P - Q * (P / Q);
END;
% COUNT, AND OPTIONALLY DISPLAY, PROPER DIVISORS OF N %
INTEGER FUNCTION DIVISORS(N, DISPLAY);
INTEGER N, DISPLAY;
BEGIN
INTEGER I, LIMIT, COUNT, START, DELTA;
IF MOD(N, 2) = 0 THEN
BEGIN
START := 2;
DELTA := 1;
END
ELSE % ONLY NEED TO CHECK ODD DIVISORS %
BEGIN
START := 3;
DELTA := 2;
END;
% 1 IS A DIVISOR OF ANY NUMBER > 1 %
IF N > 1 THEN COUNT := 1 ELSE COUNT := 0;
IF (DISPLAY <> 0) AND (COUNT <> 0) THEN WRITEON(1);
% CHECK REMAINING POTENTIAL DIVISORS %
I := START;
LIMIT := N / START;
WHILE I <= LIMIT DO
BEGIN
IF MOD(N, I) = 0 THEN
BEGIN
IF DISPLAY <> 0 THEN WRITEON(I);
COUNT := COUNT + 1;
END;
I := I + DELTA;
IF COUNT = 1 THEN LIMIT := N / I;
END;
DIVISORS := COUNT;
END;
COMMENT MAIN PROGRAM BEGINS HERE;
INTEGER I, NDIV, TRUE, FALSE, HIGHDIV, HIGHNUM;
TRUE := -1;
FALSE := 0;
WRITE("PROPER DIVISORS OF FIRST TEN NUMBERS:");
FOR I := 1 STEP 1 UNTIL 10 DO
BEGIN
WRITE(I, " : ");
NDIV := DIVISORS(I, TRUE);
END;
WRITE("SEARCHING FOR NUMBER UP TO 10000 WITH MOST DIVISORS ...");
HIGHDIV := 1;
HIGHNUM := 1;
FOR I := 1 STEP 1 UNTIL 10000 DO
BEGIN
NDIV := DIVISORS(I, FALSE);
IF NDIV > HIGHDIV THEN
BEGIN
HIGHDIV := NDIV;
HIGHNUM := I;
END;
END;
WRITE("THE NUMBER IS:", HIGHNUM);
WRITE("IT HAS", HIGHDIV, " DIVISORS");
END