WARNING: This library has been created for educational and research purposes. It is not recommended for use in production environments.
Another Big Numbers Library is developed to explore low-level features of the language and operator overloading, providing high performance objects with an easy to use interface, which each class have the same behavior of the built-in data types, or at least the most of its features are simulated.
In theory, the precision limit is defined by the size of the system memory. Despite all this, not enough tests have been performed, so it may contain several unknown critic errors. If important calculations need to be performed with arbitrary precision, the use of revised and stable libraries such as GMP is recommended.
See main.cpp for example of use.
- Written in C++98. See the other branches for C++11 (recommended) and MSVC versions
- Dependencies free
- All the classes and functions are defined inside the
bnlnamespace - Arbitrary precision integer class with all operators overloaded
- Licensed under the MIT license
The bnl::integer class provides an arbitrary precision integer implementation.
The numerical data is stored in raw binary format by a self-managed dynamic
array of unsigned long int assuming the data type is 8 bytes wide, ordered
from the least significant to the most significant data block. Each block of
data can store values in the interval [0, 232) simulating a base
232 - 1 representation.
The numeric data is converting from raw binary to std::string and from
std::string to raw binary with the Double-Dabble and Reverse Double-Dabble
algorithm respectively.
All methods are own implementations and optimal performance is not guaranteed.
| Function | Description |
|---|---|
bnl::iseven |
Returns whether the value is even |
bnl::isneg |
Returns whether the value is negative |
bnl::isodd |
Returns whether the value is odd |
bnl::isone |
Returns whether the value equals to one, positive or negative |
bnl::ispos |
Returns whether the value is positive |
bnl::iszero |
Returns whether the value equals to zero |
| Function | Description |
|---|---|
bnl::abs |
Returns the absolute value of a number |
bnl::max |
Returns largest number between two numbers |
bnl::min |
Returns smaller number between two numbers |
bnl::pow |
Returns the given number raised to the given exponent |
bnl::integer::div |
Returns the quotient and remainder of integer division* |
*See bnl::div_t for more details.
| Function | Description |
|---|---|
bnl::integer::checkstr |
Check if a string has a valid decimal representation and process it |
bnl::integer::precision |
Returns the number presicion |
| Constructor | Description |
|---|---|
| Default | Creates a new instance initialized to zero |
| Copy | Creates a new instance from already existing bnl::integer |
From std::string |
Creates a new instance from std::string |
From const char * |
Creates a new instance from const char * |
From long double |
Creates a new instance from long double |
The operator are listing by descending precedence order.
| Operator | Description |
|---|---|
std::string |
Conversion to std::string |
| Operator | Description |
|---|---|
++ |
Prefix and postfix increment |
-- |
Prefix and postfix decrement |
| Operator | Description |
|---|---|
+ |
Integer promotion |
- |
Additive inverse |
! |
Logical NOT |
~ |
Bitwise NOT (one's complement) |
| Operator | Description |
|---|---|
* |
Multiplication |
/ |
Division |
% |
Modulo |
+ |
Addition |
- |
Subtraction |
<< |
Left shift, also used for I/O |
>> |
Right shift, also used for I/O |
| Operator | Description |
|---|---|
> |
Greater than |
< |
Less than |
>= |
Greater than or equal to |
<= |
Less than or equal to |
== |
Equal to |
!= |
Not equal to |
| Operator | Description |
|---|---|
& |
Bitwise AND |
| |
Bitwise OR (inclusive or) |
^ |
Bitwise XOR (exclusive or) |
| Operator | Description |
|---|---|
&& |
Logical AND |
|| |
Logical OR |
| Operator | Description |
|---|---|
= |
Direct assignation |
+= |
Assignation by addition |
-= |
Assignation by subtraction |
*= |
Assignation by multiplication |
/= |
Assignation by division |
%= |
Assignation by modulo |
<<= |
Assignation by left shift |
>>= |
Assignation by right shift |
&= |
Assignation by bitwise AND |
|= |
Assignation by bitwise OR |
^= |
Assignation by bitwise XOR |
Similar to std::div_t defined in cmath, represents the result value of an
integral division performed by function bnl::integer::div.
It has two int members: quot and rem.
| Member | Description |
|---|---|
quot |
Represents the quotient of the integral division |
rem |
Represents the remainder of the integral division |
Since the code is written in C++98 standard and is dependencies free, can be compiled by most compilers, but some data sizes have been assumed, so not defined errors may occurs if the target system have different data types sizes to the next table.
| Data type | Size in bytes |
|---|---|
unsigned char |
1 |
unsigned int |
4 |
unsigned long int |
8 |
long double |
16 |
However, the C++11 version is recommended to avoid portability issues. A version for MSVC is also available.