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/* ************************************************************** * C++ Mathematical Expression Toolkit Library * * * * ExprTk Sieve Of Eratosthenes * * Author: Arash Partow (1999-2024) * * URL: https://www.partow.net/programming/exprtk/index.html * * * * Copyright notice: * * Free use of the Mathematical Expression Toolkit Library is * * permitted under the guidelines and in accordance with the * * most current version of the MIT License. * * https://www.opensource.org/licenses/MIT * * SPDX-License-Identifier: MIT * * * ************************************************************** */ #include #include #include "exprtk.hpp" template void sieve_of_eratosthenes() { typedef exprtk::expression expression_t; typedef exprtk::parser parser_t; const std::string sieve_of_eratosthenes_program = " var sieve[10^8] := [false]; " " var m := trunc(sqrt(sieve[])); " " " " sieve[0] := true; " " sieve[1] := true; " " " " for (var i := 0; i <= m; i += 1) " " { " " if (false == sieve[i]) " " { " " for (var j := i^2; j < sieve[]; j += i) " " { " " sieve[j] := true; " " } " " } " " }; " " " " var prime_count := sieve[] - sum(sieve); " " " " prime_count == 5761455; "; expression_t expression; parser_t parser; parser.compile(sieve_of_eratosthenes_program,expression); exprtk::timer timer; timer.start(); const T result = expression.value(); timer.stop(); printf("Result: %8.3f\n",result); printf("Total time: %8.3fsec\n",timer.time()); } int main() { sieve_of_eratosthenes(); return 0; }