Largest prime factor: Difference between revisions

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@@ Line 23: / Line 23: @@
              # odd factors #
              LONG INT k := 3;
-             WHILE k * k <= n DO
+             LONG INT root n = ENTIER long sqrt( n );
-                 WHILE v MOD k = 0 DO
+             WHILE k <= root n AND v > 1 DO
+                 WHILE v MOD k = 0 AND v > 1 DO
                      max factor := k;
                      v OVERAB k
@@ Line 32: / Line 33: @@
              IF v > 1 THEN v ELSE max factor FI
         FI # max prime factor # ;
+    # test the max prime factor routine #
-    LONG INT n = 600 851 475 143;
+    PROC test = ( LONG INT n )VOID:
-    print( ( "Largest prime factor of ", whole( n, 0 ), " is ", whole( max prime factor( n ), 0 ), newline ) )
+         print( ( "Largest prime factor of ", whole( n, 0 ), " is ", whole( max prime factor( n ), 0 ), newline ) );
+    # test cases #
+    test( 600 851 475 143 );
+    test(           6 008 );
+    test(             751 )
 END</lang>
 {{out}}
 <pre>
 Largest prime factor of 600851475143 is 6857
+Largest prime factor of 6008 is 751
+Largest prime factor of 751 is 751
 </pre>