exprtk/exprtk_simple_example_02.cpp at master · losttem/exprtk · GitHub

History

73 lines (59 loc) · 2.34 KB

Raw

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

* C++ Mathematical Expression Toolkit Library *

* *

* Simple Example 2 *

* Author: Arash Partow (1999-2022) *

* URL: http://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. *

* http://www.opensource.org/licenses/MIT *

* *

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

#include <cstdio>

#include <string>

#include "exprtk.hpp"

template <typename T>

void square_wave()

{

typedef exprtk::symbol_table<T> symbol_table_t;

typedef exprtk::expression<T> expression_t;

typedef exprtk::parser<T> parser_t;

const std::string expr_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(expr_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);

}

int main()

{

square_wave<double>();

return 0;

}

exprtk/exprtk_simple_example_02.cpp at master · losttem/exprtk · GitHub

Expand file tree

Breadcrumbs

exprtk_simple_example_02.cpp

Latest commit

History

Breadcrumbs

exprtk_simple_example_02.cpp

File metadata and controls