https://github.com/kimwalisch/calculator

C++ operator precedence parser
https://github.com/kimwalisch/calculator

c-plus-plus calculator

Last synced: about 2 months ago
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C++ operator precedence parser

• Host: GitHub
• URL: https://github.com/kimwalisch/calculator
• Owner: kimwalisch
• License: bsd-2-clause
• Created: 2013-11-08T09:29:27.000Z (almost 11 years ago)
• Default Branch: master
• Last Pushed: 2024-03-10T18:11:43.000Z (7 months ago)
• Last Synced: 2024-06-14T12:50:39.481Z (3 months ago)
• Topics: c-plus-plus, calculator
• Language: C++
• Size: 28.3 KB
• Stars: 94
• Watchers: 12
• Forks: 63
• Open Issues: 3
• Metadata Files:
  • Readme: README.md
  • License: COPYING

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README

        
# calculator

```calculator.hpp``` is a header-only C++ library for parsing and

evaluating integer arithmetic expressions e.g. ```"10 * (7 - 1)"```. It compiles with any

C++ compiler and works with any integer type e.g. ```int```,

```long```, ```uint64_t```.

calculator is a simple but fast

[operator-precedence parser](https://en.wikipedia.org/wiki/Operator-precedence_parser). 

# Supported operators

```calculator.hpp``` uses the same operator precedence and associativity

as the C++ programming language and also supports the power operator.

  

    Operator

    Description

  

  

    |

    Bitwise Inclusive OR

  

  

    ^

    Bitwise Exclusive OR

  

  

    &

    Bitwise AND

  

  

    ~

    Unary Complement 

  

  

    <<

    Shift Left

  

  

    >>

    Shift Right

  

  

    +

    Addition

  

  

    -

    Subtraction

  

  

    *

    Multiplication

  

  

    /

    Division

  

  

    %

    Modulo

  

  

    **

    Raise to power

  

# C++ API

Functions defined in ```calculator.hpp```.

```C++

int calculator::eval(const std::string& expression);

template 

T calculator::eval(const std::string& expression);

```

# How to use it

```calculator::eval("1+2")``` takes a string with an integer arithmetic

expression as an argument, evaluates the arithmetic expression and returns

the result. If the expression string is not a valid integer arithmetic

expression a ```calculator::error``` exception is thrown.

```C++

#include "calculator.hpp"

#include 

#include 

int main()

{

    try

    {

        int result = calculator::eval("(0 + ~(255 & 1000)*3) / -2");

        std::cout << result << std::endl;

    

        // 64-bit arithmetic

        int64_t r64 = calculator::eval("2**60");

        std::cout << r64 << std::endl;

    }

    catch (calculator::error& e)

    {

        std::cerr << e.what() << std::endl;

    }

    return 0;

}

```