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/* ************************************************************** * C++ Mathematical Expression Toolkit Library * * * * ExprTk Collatz Example * * 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 #include #include "exprtk.hpp" template void collatz() { typedef exprtk::symbol_table symbol_table_t; typedef exprtk::expression expression_t; typedef exprtk::parser parser_t; typedef exprtk::function_compositor compositor_t; typedef typename compositor_t::function function_t; exprtk::rtl::io::print print("%3.0f "); symbol_table_t symbol_table; symbol_table.add_function("print",print); compositor_t compositor(symbol_table); // define function: collatz_trace(x) compositor.add( function_t("collatz_trace") .var("x") .expression ( " while (x > 1) " " { " " x := (x % 2 == 0) ? x / 2 : 3x + 1; " " print(x); " " } " )); const std::string collatz_program = " x := 0; " " repeat " " print(x += 1); " " collatz_trace(x); " " print('\n\n'); " " until (x > 100); " " println; "; expression_t expression; expression.register_symbol_table(symbol_table); parser_t parser; parser.enable_unknown_symbol_resolver(); parser.compile(collatz_program,expression); expression.value(); } int main() { collatz(); return 0; }