181 lines
6.9 KiB
C++
181 lines
6.9 KiB
C++
/*
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**************************************************************
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* C++ Mathematical Expression Toolkit Library *
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* *
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* Simple Example 09 *
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* Author: Arash Partow (1999-2024) *
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* URL: https://www.partow.net/programming/exprtk/index.html *
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* *
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* Copyright notice: *
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* Free use of the Mathematical Expression Toolkit Library is *
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* permitted under the guidelines and in accordance with the *
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* most current version of the MIT License. *
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* https://www.opensource.org/licenses/MIT *
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* SPDX-License-Identifier: MIT *
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* *
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**************************************************************
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*/
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#include <cstdio>
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#include <string>
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#include "exprtk.hpp"
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template <typename T>
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void primes()
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{
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typedef exprtk::symbol_table<T> symbol_table_t;
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typedef exprtk::expression<T> expression_t;
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typedef exprtk::parser<T> parser_t;
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typedef exprtk::function_compositor<T> compositor_t;
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typedef typename compositor_t::function function_t;
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T x = T(0);
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symbol_table_t symbol_table;
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symbol_table.add_constants();
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symbol_table.add_variable("x",x);
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compositor_t compositor(symbol_table);
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//Mode 1 - if statement based
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compositor.add(
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function_t("is_prime_impl1")
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.vars("x", "y")
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.expression
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(
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" if (y == 1,true, "
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" if (0 == (x % y),false, "
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" is_prime_impl1(x,y - 1))) "
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));
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compositor.add(
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function_t("is_prime1")
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.var("x")
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.expression
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(
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" if (frac(x) != 0) "
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" return [false]; "
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" else if (x <= 0) "
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" return [false]; "
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" else "
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" is_prime_impl1(x,min(x - 1,trunc(sqrt(x)) + 1)); "
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));
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//Mode 2 - switch statement based
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compositor.add(
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function_t("is_prime_impl2")
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.vars("x", "y")
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.expression
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(
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" switch "
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" { "
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" case y == 1 : true; "
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" case (x % y) == 0 : false; "
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" default : is_prime_impl2(x,y - 1); "
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" } "
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));
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compositor.add(
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function_t("is_prime2")
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.var("x")
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.expression
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(
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" switch "
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" { "
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" case x <= 0 : false; "
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" case frac(x) != 0 : false; "
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" default : is_prime_impl2(x,min(x - 1,trunc(sqrt(x)) + 1)); "
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" } "
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));
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//Mode 3 - switch statement and for-loop based
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compositor.add(
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function_t("is_prime3")
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.var("x")
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.expression
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(
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" switch "
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" { "
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" case x <= 1 : return [false]; "
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" case frac(x) != 0 : return [false]; "
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" case x == 2 : return [true ]; "
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" }; "
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" "
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" var prime_lut[27] := "
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" { "
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" 2, 3, 5, 7, 11, 13, 17, 19, 23, "
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" 29, 31, 37, 41, 43, 47, 53, 59, 61, "
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" 67, 71, 73, 79, 83, 89, 97, 101, 103 "
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" }; "
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" "
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" var upper_bound := min(x - 1, trunc(sqrt(x)) + 1); "
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" "
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" for (var i := 0; i < prime_lut[]; i += 1) "
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" { "
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" if (prime_lut[i] >= upper_bound) "
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" return [true]; "
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" else if ((x % prime_lut[i]) == 0) "
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" return [false]; "
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" }; "
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" "
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" var lower_bound := prime_lut[prime_lut[] - 1] + 2; "
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" "
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" for (var i := lower_bound; i < upper_bound; i += 2) "
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" { "
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" if ((x % i) == 0) "
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" { "
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" return [false]; "
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" } "
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" }; "
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" "
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" return [true]; "
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));
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std::string expression_str1 = "is_prime1(x)";
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std::string expression_str2 = "is_prime2(x)";
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std::string expression_str3 = "is_prime3(x)";
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expression_t expression1;
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expression_t expression2;
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expression_t expression3;
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expression1.register_symbol_table(symbol_table);
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expression2.register_symbol_table(symbol_table);
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expression3.register_symbol_table(symbol_table);
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parser_t parser;
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parser.compile(expression_str1, expression1);
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parser.compile(expression_str2, expression2);
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parser.compile(expression_str3, expression3);
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for (std::size_t i = 0; i < 15000; ++i)
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{
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x = static_cast<T>(i);
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const T result1 = expression1.value();
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const T result2 = expression2.value();
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const T result3 = expression3.value();
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const bool results_concur = (result1 == result2) &&
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(result1 == result3) ;
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printf("%03d Result1: %c Result2: %c Result3: %c "
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"Results Concur: %c\n",
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static_cast<unsigned int>(i),
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(result1 == T(1)) ? 'T' : 'F',
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(result2 == T(1)) ? 'T' : 'F',
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(result3 == T(1)) ? 'T' : 'F',
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(results_concur) ? 'T' : 'F');
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}
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}
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int main()
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{
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primes<double>();
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return 0;
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}
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