67 lines
1.8 KiB
C++
67 lines
1.8 KiB
C++
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/*
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**************************************************************
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* C++ Mathematical Expression Toolkit Library *
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* *
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* Simple Example 5 *
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* Author: Arash Partow (1999-2013) *
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* URL: http://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 Common Public License. *
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* http://www.opensource.org/licenses/cpl1.0.php *
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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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struct myfunc : public exprtk::ifunction<T>
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{
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myfunc()
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: exprtk::ifunction<T>(2)
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{}
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inline T operator()(const T& v1, const T& v2)
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{
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return T(1) + (v1 * v2) / T(3);
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}
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};
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template<typename T>
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void custom_function()
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{
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typedef exprtk::expression<T> expression_t;
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std::string expression_string = "myfunc(sin(x*pi),y/2)";
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T x = T(1.0);
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T y = T(2.0);
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myfunc<T> mf;
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exprtk::symbol_table<T> symbol_table;
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symbol_table.add_variable("x",x);
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symbol_table.add_variable("y",y);
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symbol_table.add_function("myfunc",mf);
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symbol_table.add_constants();
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expression_t expression;
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expression.register_symbol_table(symbol_table);
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exprtk::parser<T> parser;
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parser.compile(expression_string,expression);
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T result = expression.value();
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printf("Result: %10.5f\n",result);
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}
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int main()
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{
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custom_function<double>();
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return 0;
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}
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