Primality by trial division: Difference between revisions

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 {{works with|QuickBasic|4.5}}
-Going with the classic 1 for "true" and 0 for "false":
+Returns 1 for prime, 0 for non-prime
- FUNCTION prime% (n!)
-   IF n = 2 THEN prime = 1
-   IF n <= 1 OR n MOD 2 = 0 THEN prime = 0
-   FOR a = 3 TO INT(SQR(n)) STEP 2
-     IF n MOD a = 0 THEN prime = 0
-   NEXT a
-   prime = 1
- END FUNCTION
+<lang BASIC>FUNCTION prime% (n!)
+  STATIC i AS INTEGER
+  IF n = 2 OR n = 3 THEN
+    prime = 1
+  ELSEIF n <= 1 OR n MOD 2 = 0 THEN
+    prime = 0
+  ELSE
+    prime = 1
+    FOR i = 3 TO INT(SQR(n)) STEP 2
+      IF n MOD i = 0 THEN
+        prime = 0
+        EXIT FUNCTION
+      END IF
+    NEXT i
+  END IF
+END FUNCTION
+' Test and display primes 1 .. 50
+DECLARE FUNCTION prime% (n!)
+FOR n = 1 TO 50
+  IF prime(n) = 1 THEN PRINT n;
+NEXT n</lang>
+Output:
+<pre> 2  3  5  7  11  13  17  19  23  29  31  37  41  43  47</pre>
 =={{header|C}}==