exprtk_sumofprimes.cpp

/*
 **************************************************************
 *         C++ Mathematical Expression Toolkit Library        *
 *                                                            *
 * ExprTk Summation of Prime Factors                          *
 * Author: Arash Partow (1999-2021)                           *
 * 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 <iostream>
#include <string>

#include "exprtk.hpp"


template <typename T>
void sum_of_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;

   symbol_table_t symbol_table;

   compositor_t compositor(symbol_table);

   compositor
      .add( // define function: sum_of_primes(z)
         function_t("sum_of_primes")
           .var("z")
           .expression(
             " var i     := 2;     "
             " var total := 0;     "
             " while (z > 1)       "
             " {                   "
             "   if (0 == (z % i)) "
             "   {                 "
             "     total += i;     "
             "     z /= i;         "
             "   }                 "
             "   else              "
             "     i += 1;         "
             " };                  "
             " total;              "));

   exprtk::rtl::io::println<T> println;

   symbol_table.add_function("println",println);

   const std::string sum_of_primes_program =
                        " for (var i := 1; i <= 100; i += 1) "
                        " {                                  "
                        "   println(i, sum_of_primes(i));    "
                        " }                                  ";

   expression_t expression;
   expression.register_symbol_table(symbol_table);

   parser_t parser;
   parser.compile(sum_of_primes_program,expression);

   expression.value();
}

int main()
{
   sum_of_primes<double>();
   return 0;
}