/
exprtk_simple_example_09.cpp
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/
exprtk_simple_example_09.cpp
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/*
**************************************************************
* C++ Mathematical Expression Toolkit Library *
* *
* Simple Example 9 *
* Author: Arash Partow (1999-2023) *
* 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 *
* *
**************************************************************
*/
#include <cstdio>
#include <string>
#include "exprtk.hpp"
template <typename T>
void primes()
{
typedef exprtk::symbol_table<T> symbol_table_t;
typedef exprtk::expression<T> expression_t;
typedef exprtk::parser<T> parser_t;
typedef exprtk::function_compositor<T> compositor_t;
typedef typename compositor_t::function function_t;
T x = T(0);
symbol_table_t symbol_table;
symbol_table.add_constants();
symbol_table.add_variable("x",x);
compositor_t compositor(symbol_table);
//Mode 1 - if statement based
compositor
.add(
function_t( // define function: is_prime_impl1(x,y)
"is_prime_impl1",
" if (y == 1,true, "
" if (0 == (x % y),false, "
" is_prime_impl1(x,y - 1))) ",
"x","y"));
compositor
.add(
function_t( // define function: is_prime1(x)
"is_prime1",
" if (frac(x) != 0, false, "
" if (x <= 0, false, "
" is_prime_impl1(x,min(x - 1,trunc(sqrt(x)) + 1)))) ",
"x"));
//Mode 2 - switch statement based
compositor
.add(
function_t( // define function: is_prime_impl2(x,y)
"is_prime_impl2",
" switch "
" { "
" case y == 1 : true; "
" case (x % y) == 0 : false; "
" default : is_prime_impl2(x,y - 1); "
" } ",
"x","y"));
compositor
.add(
function_t( // define function: is_prime2(x)
"is_prime2",
" switch "
" { "
" case x <= 0 : false; "
" case frac(x) != 0 : false; "
" default : is_prime_impl2(x,min(x - 1,trunc(sqrt(x)) + 1)); "
" } ",
"x"));
//Mode 3 - switch statement and while-loop based
compositor
.add(
function_t( // define function: is_prime_impl3(x,y)
"is_prime_impl3",
" while (y > 0) "
" { "
" switch "
" { "
" case y == 1 : ~(y := 0,true); "
" case (x % y) == 0 : ~(y := 0,false); "
" default : y := y - 1; "
" } "
" } ",
"x","y"));
compositor
.add(
function_t( // define function: is_prime3(x)
"is_prime3",
" switch "
" { "
" case x <= 0 : false; "
" case frac(x) != 0 : false; "
" default : is_prime_impl3(x,min(x - 1,trunc(sqrt(x)) + 1)); "
" } ",
"x"));
std::string expression_str1 = "is_prime1(x)";
std::string expression_str2 = "is_prime2(x)";
std::string expression_str3 = "is_prime3(x)";
expression_t expression1;
expression_t expression2;
expression_t expression3;
expression1.register_symbol_table(symbol_table);
expression2.register_symbol_table(symbol_table);
expression3.register_symbol_table(symbol_table);
parser_t parser;
parser.compile(expression_str1,expression1);
parser.compile(expression_str2,expression2);
parser.compile(expression_str3,expression3);
for (std::size_t i = 0; i < 100; ++i)
{
x = static_cast<T>(i);
const T result1 = expression1.value();
const T result2 = expression2.value();
const T result3 = expression3.value();
printf("%03d Result1: %c Result2: %c Result3: %c\n",
static_cast<unsigned int>(i),
(result1 == T(1)) ? 'T' : 'F',
(result2 == T(1)) ? 'T' : 'F',
(result3 == T(1)) ? 'T' : 'F');
}
}
int main()
{
primes<double>();
return 0;
}