exprtk/exprtk_simple_example_05.cpp at master · ArashPartow/exprtk · GitHub

History

82 lines (66 loc) · 2.24 KB

Raw

**************************************************************

* C++ Mathematical Expression Toolkit Library *

* *

* Simple Example 05 *

* Author: Arash Partow (1999-2025) *

* 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 <cstdio>

#include <string>

#include "exprtk.hpp"

template <typename T>

struct myfunc : public exprtk::ifunction<T>

{

using exprtk::ifunction<T>::operator();

myfunc()

: exprtk::ifunction<T>(2)

{ exprtk::disable_has_side_effects(*this); }

T operator()(const T& v1, const T& v2)

{

return T(1) + (v1 * v2) / T(3);

}

};

template <typename T>

T myotherfunc(T v0, T v1, T v2)

{

return std::abs(v0 - v1) * v2;

}

template <typename T>

void custom_function()

{

typedef exprtk::symbol_table<T> symbol_table_t;

typedef exprtk::expression<T> expression_t;

typedef exprtk::parser<T> parser_t;

const std::string expression_string =

"myfunc(sin(x / pi), otherfunc(3 * y, x / 2, x * y))";

T x = T(1);

T y = T(2);

myfunc<T> mf;

symbol_table_t symbol_table;

symbol_table.add_variable("x",x);

symbol_table.add_variable("y",y);

symbol_table.add_function("myfunc",mf);

symbol_table.add_function("otherfunc",myotherfunc);

symbol_table.add_constants();

expression_t expression;

expression.register_symbol_table(symbol_table);

parser_t parser;

parser.compile(expression_string,expression);

const T result = expression.value();

printf("Result: %10.5f\n",result);

}

int main()

{

custom_function<double>();

return 0;

}

exprtk/exprtk_simple_example_05.cpp at master · ArashPartow/exprtk · GitHub

Expand file tree

Breadcrumbs

exprtk_simple_example_05.cpp

Latest commit

History

Breadcrumbs

exprtk_simple_example_05.cpp

File metadata and controls