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/* ************************************************************** * C++ Mathematical Expression Toolkit Library * * * * Vector Resize 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 #include "exprtk.hpp" template void vector_resize_example() { typedef exprtk::symbol_table symbol_table_t; typedef exprtk::expression expression_t; typedef exprtk::parser parser_t; std::vector v0 = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 }; std::vector v1 = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 }; exprtk::vector_view vv = exprtk::make_vector_view(v0, v0.size()); T n = T(0); symbol_table_t symbol_table; symbol_table.add_variable("n", n); symbol_table.add_vector ("v", vv); expression_t expression; expression.register_symbol_table(symbol_table); parser_t parser; const std::string vector_resize_expression = " sum(v) == ((v[]^2 + v[]) / 2) and sum(2v) == (n^2 + n)"; if (!parser.compile(vector_resize_expression, expression)) { printf("Error: %s\tExpression: %s\n", parser.error().c_str(), vector_resize_expression.c_str()); return; } for (std::size_t i = 1; i <= vv.base_size(); ++i) { vv.set_size(i); vv.rebase(i % 2 ? v0.data() : v1.data()); n = T(i); const T result = expression.value(); if (result != T(1)) { printf("Error: vector size: %d\n", static_cast(i)); } } } int main() { vector_resize_example(); return 0; } /* Build: c++ -pedantic-errors -Wall -Wextra -Werror -O3 -DNDEBUG -o vector_resize_example01 vector_resize_example01.cpp -L/usr/lib -lstdc++ -lm */