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| author | Sven Eisenhauer <sven@sven-eisenhauer.net> | 2023-11-10 15:11:48 +0100 |
|---|---|---|
| committer | Sven Eisenhauer <sven@sven-eisenhauer.net> | 2023-11-10 15:11:48 +0100 |
| commit | 33613a85afc4b1481367fbe92a17ee59c240250b (patch) | |
| tree | 670b842326116b376b505ec2263878912fca97e2 /Bachelor/Prog2/Codebeispiele/7_ch21/fig21_40.CPP | |
| download | Studium-33613a85afc4b1481367fbe92a17ee59c240250b.tar.gz Studium-33613a85afc4b1481367fbe92a17ee59c240250b.tar.bz2 | |
Diffstat (limited to 'Bachelor/Prog2/Codebeispiele/7_ch21/fig21_40.CPP')
| -rw-r--r-- | Bachelor/Prog2/Codebeispiele/7_ch21/fig21_40.CPP | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/Bachelor/Prog2/Codebeispiele/7_ch21/fig21_40.CPP b/Bachelor/Prog2/Codebeispiele/7_ch21/fig21_40.CPP new file mode 100644 index 0000000..e1d8a91 --- /dev/null +++ b/Bachelor/Prog2/Codebeispiele/7_ch21/fig21_40.CPP @@ -0,0 +1,82 @@ +// Fig. 21.40: fig21_40.cpp
+// Using a bitset to demonstrate the Sieve of Eratosthenes.
+#include <iostream>
+
+using std::cin;
+using std::cout;
+using std::endl;
+
+#include <iomanip>
+
+using std::setw;
+
+#include <bitset> // bitset class definition
+#include <cmath> // sqrt prototype
+
+int main()
+{
+ const int size = 1024;
+ int value;
+ std::bitset< size > sieve;
+
+ sieve.flip();
+
+ // perform Sieve of Eratosthenes
+ int finalBit = sqrt( sieve.size() ) + 1;
+
+ for ( int i = 2; i < finalBit; ++i )
+
+ if ( sieve.test( i ) )
+
+ for ( int j = 2 * i; j < size; j += i )
+ sieve.reset( j );
+
+ cout << "The prime numbers in the range 2 to 1023 are:\n";
+
+ // display prime numbers in range 2-1023
+ for ( int k = 2, counter = 0; k < size; ++k )
+
+ if ( sieve.test( k ) ) {
+ cout << setw( 5 ) << k;
+
+ if ( ++counter % 12 == 0 )
+ cout << '\n';
+
+ } // end outer if
+
+ cout << endl;
+
+ // get value from user to determine whether value is prime
+ cout << "\nEnter a value from 1 to 1023 (-1 to end): ";
+ cin >> value;
+
+ while ( value != -1 ) {
+
+ if ( sieve[ value ] )
+ cout << value << " is a prime number\n";
+ else
+ cout << value << " is not a prime number\n";
+
+ cout << "\nEnter a value from 2 to 1023 (-1 to end): ";
+ cin >> value;
+
+ } // end while
+
+ return 0;
+
+} // end main
+
+/**************************************************************************
+ * (C) Copyright 1992-2003 by Deitel & Associates, Inc. and Prentice *
+ * Hall. All Rights Reserved. *
+ * *
+ * DISCLAIMER: The authors and publisher of this book have used their *
+ * best efforts in preparing the book. These efforts include the *
+ * development, research, and testing of the theories and programs *
+ * to determine their effectiveness. The authors and publisher make *
+ * no warranty of any kind, expressed or implied, with regard to these *
+ * programs or to the documentation contained in these books. The authors *
+ * and publisher shall not be liable in any event for incidental or *
+ * consequential damages in connection with, or arising out of, the *
+ * furnishing, performance, or use of these programs. *
+ *************************************************************************/
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