exprtk_simple_example_01.cpp

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/*
 **************************************************************
 *         C++ Mathematical Expression Toolkit Library        *
 *                                                            *
 * Simple Example 01                                          *
 * 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 <cstdio>
#include <string>
 
#include "exprtk.hpp"
 
 
template <typename T>
void trig_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 =
      "clamp(-1.0, sin(2 * pi * x) + cos(x / 2 * pi), +1.0)";
 
   T x;
 
   symbol_table_t symbol_table;
   symbol_table.add_variable("x",x);
   symbol_table.add_constants();
 
   expression_t expression;
   expression.register_symbol_table(symbol_table);
 
   parser_t parser;
   parser.compile(expression_string,expression);
 
   for (x = T(-5); x <= T(+5); x += T(0.001))
   {
      const T y = expression.value();
      printf("%19.15f\t%19.15f\n", x, y);
   }
}
 
int main()
{
   trig_function<double>();
   return 0;
}