home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Fritz: All Fritz
/
All Fritz.zip
/
All Fritz
/
FILES
/
PROGMISC
/
ALGOL.LZH
/
ERAT.SP
< prev
next >
Wrap
Text File
|
1983-10-25
|
2KB
|
70 lines
BEGIN
COMMENT Sieve of Eratosthenes program to calculate
prime numbers. ;
REAL Time_in_seconds; { Output argument of PROCEDURE
Compute_time_in_seconds. }
PROCEDURE Compute_time_in_seconds;
BEGIN
STRING Time_string; { This holds the current time. }
Time_string:=TIME$; { HH:MM:SS }
Time_in_seconds:=VAL(MID$(Time_string,1,2))*3600 {Hours * 3600}
+VAL(MID$(Time_string,4,2))*60 {Minutes*60 added}
+VAL(MID$(Time_string,7,2)); {Seconds added}
{ The time in seconds are now computed. }
END
INTEGER ARRAY FLAGS(8191); {Prime number flags.}
INTEGER I,M,K,PRIME,COUNT; {Loop variables,prime number counter.}
REAL Start_time, {Start time of test}
Finish_time; {Finish time for ten iterations.}
Compute_time_in_seconds; {Compute the current time.}
Start_time:=Time_in_seconds; {Set Start time.}
OUTPUT('Time is:' + TIME$);
FOR M := 1 STEP 1 UNTIL 10 DO
BEGIN
COUNT := 0;
FOR I := 1 STEP 1 UNTIL 8191 DO
BEGIN
FLAGS(I) := 1;
END
FOR I := 1 STEP 1 UNTIL 8191 DO
BEGIN
IF FLAGS(I) = 1 THEN
BEGIN
PRIME := I+I+3;
K := I+PRIME;
WHILE K <= 8191 DO
BEGIN
FLAGS(K) := 0;
K := K+PRIME;
END
COUNT := COUNT+1;
END
END
END
Compute_time_in_seconds; {Compute the current time.}
Finish_time:=Time_in_seconds; {Set Finish time.}
OUTPUT('Time is:' + TIME$); OUTPUT();
OUTPUT(COUNT @ ' PRIMES for each of Ten iterations.'); OUTPUT();
OUTPUT('Time for one iteration is:' @
(Finish_time - Start_time)/10.
@ ' seconds.');
END