exprtk_simple_example_02.cpp File Reference

#include <cstdio>
#include <string>
#include "exprtk.hpp"

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Functions
template<typename T >
void	square_wave ()
int	main ()

Function Documentation

main()

int main

(

)

Definition at line 70 of file exprtk_simple_example_02.cpp.

{
   square_wave<double>();
   return 0;
}

square_wave()

template<typename T >

void square_wave

(

)

Definition at line 27 of file exprtk_simple_example_02.cpp.

{
   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 =
      "a *(4 / pi) * "
      "((1 /  1) * sin( 2 * pi * f * t) + (1 /  3) * sin( 6 * pi * f * t) + "
      " (1 /  5) * sin(10 * pi * f * t) + (1 /  7) * sin(14 * pi * f * t) + "
      " (1 /  9) * sin(18 * pi * f * t) + (1 / 11) * sin(22 * pi * f * t) + "
      " (1 / 13) * sin(26 * pi * f * t) + (1 / 15) * sin(30 * pi * f * t) + "
      " (1 / 17) * sin(34 * pi * f * t) + (1 / 19) * sin(38 * pi * f * t) + "
      " (1 / 21) * sin(42 * pi * f * t) + (1 / 23) * sin(46 * pi * f * t) + "
      " (1 / 25) * sin(50 * pi * f * t) + (1 / 27) * sin(54 * pi * f * t))  ";
 
   static const T pi = T(3.141592653589793238462643383279502);
 
   const T f = pi / T(10);
   const T a = T(10);
         T t = T(0);
 
   symbol_table_t symbol_table;
   symbol_table.add_variable("t",t);
   symbol_table.add_constant("f",f);
   symbol_table.add_constant("a",a);
   symbol_table.add_constants();
 
   expression_t expression;
   expression.register_symbol_table(symbol_table);
 
   parser_t parser;
   parser.compile(expression_string,expression);
 
   const T delta = (T(4) * pi) / T(1000);
 
   for (t = (T(-2) * pi); t <= (T(+2) * pi); t += delta)
   {
      const T result = expression.value();
      printf("%19.15f\t%19.15f\n", t, result);
   }
}

References delta, and pi.