Google C++ Testing Framework 1.8.1HEADmaster

1 files changed, 8 insertions, 5 deletions

diff --git a/samples/prime_tables.h b/samples/prime_tables.h
index 92ce16a..523c50b 100644
--- a/samples/prime_tables.h
+++ b/samples/prime_tables.h
@@ -26,9 +26,8 @@
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-//
-// Author: wan@google.com (Zhanyong Wan)
-// Author: vladl@google.com (Vlad Losev)
+
+
 
 // This provides interface PrimeTable that determines whether a number is a
 // prime and determines a next prime number. This interface is used
@@ -103,11 +102,15 @@ class PreCalculatedPrimeTable : public PrimeTable {
     ::std::fill(is_prime_, is_prime_ + is_prime_size_, true);
     is_prime_[0] = is_prime_[1] = false;
 
-    for (int i = 2; i <= max; i++) {
+    // Checks every candidate for prime number (we know that 2 is the only even
+    // prime).
+    for (int i = 2; i*i <= max; i += i%2+1) {
       if (!is_prime_[i]) continue;
 
       // Marks all multiples of i (except i itself) as non-prime.
-      for (int j = 2*i; j <= max; j += i) {
+      // We are starting here from i-th multiplier, because all smaller
+      // complex numbers were already marked.
+      for (int j = i*i; j <= max; j += i) {
         is_prime_[j] = false;
       }
     }