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C++ Mathematical Expression Library (ExprTk) http://www.partow.net/programming/exprtk/index.html

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This commit is contained in:
Arash Partow
2020-01-01 00:00:00 +00:00
parent f32d2b4bbb
commit e67b22afd9
25 changed files with 3701 additions and 1792 deletions
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42
exprtk_simple_example_10.cpp
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@ -3,7 +3,7 @@
* C++ Mathematical Expression Toolkit Library *
* *
* Simple Example 10 *
* Author: Arash Partow (1999-2018) *
* Author: Arash Partow (1999-2020) *
* URL: http://www.partow.net/programming/exprtk/index.html *
* *
* Copyright notice: *
@ -19,6 +19,7 @@
#include <cmath>
#include <cstdio>
#include <string>
#include "exprtk.hpp"
@ -44,25 +45,26 @@ void newton_sqrt()
.add(
function_t( // define function: newton_sqrt(x)
"newton_sqrt",
" switch "
" { "
" case x < 0 : -inf; "
" case x == 0 : 0; "
" case x == 1 : 1; "
" default: "
" ~{ "
" var z := 100; "
" var sqrt_x := x / 2; "
" repeat "
" sqrt_x := (1 / 2) * (sqrt_x + (x / sqrt_x)); "
" if (equal(sqrt_x^2, x)) "
" break[sqrt_x]; "
" until ((z -= 1) <= 0); "
" }; "
" } ",
" switch "
" { "
" case x < 0 : null; "
" case x == 0 : 0; "
" case x == 1 : 1; "
" default: "
" ~{ "
" var z := 100; "
" var sqrt_x := x / 2; "
" repeat "
" if (equal(sqrt_x^2, x)) "
" break[sqrt_x]; "
" else "
" sqrt_x := (1 / 2) * (sqrt_x + (x / sqrt_x)); "
" until ((z -= 1) <= 0); "
" }; "
" } ",
"x"));
std::string expression_str = "newton_sqrt(x)";
const std::string expression_str = "newton_sqrt(x)";
expression_t expression;
expression.register_symbol_table(symbol_table);
@ -74,9 +76,9 @@ void newton_sqrt()
{
x = static_cast<T>(i);
T result = expression.value();
const T result = expression.value();
printf("sqrt(%03d) - Result: %12.10f\tReal: %12.10f\n",
printf("sqrt(%03d) - Result: %15.13f\tReal: %15.13f\n",
static_cast<unsigned int>(i),
result,
std::sqrt(x));