Primality by trial division: Difference between revisions
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end if;
end Test_Prime;</syntaxhighlight>
=={{header|ALGOL 60}}==
<works with|A60>
<syntax highlight lang = "algol">
begin
boolean procedure isprime(n);
value n; integer n;
begin
comment - local procedure tests whether n is even;
boolean procedure even(n);
value n; integer n;
even := entier(n / 2) * 2 = n;
if n < 2 then
isprime := false
else if even(n) then
isprime := (n = 2)
else
begin
comment - check odd divisors up to sqrt(n);
integer i, limit;
boolean divisible;
i := 3;
limit := entier(sqrt(n));
divisible := false;
for i := i while i <= limit and not divisible do
begin
if entier(n / i) * i = n then
divisible := true;
i := i + 2
end;
isprime := if divisible then false else true;
end;
end;
comment - exercise the procedure;
integer i;
outstring(1,"Testing first 50 numbers for primality:\n");
for i := 1 step 1 until 50 do
if isprime(i) then
outinteger(1,i);
end
</syntaxhighlight>
{{out}}
<pre>
Testing first 50 numbers for primality:
2 3 5 7 11 13 17 19 23 29 31 37 41 43 47
</pre>
=={{header|ALGOL 68}}==
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