BigInteger: A C++ repository from Raibows

C++ BigInteger

This is a normal implementation of BigInteger for C++, support the operation of much more than 2^64 or 1000 width integer. But please notice that the author@ChiZuo will not take any responsibility for any lost caused by any bugs in this respository. This implementation has a not bad performance in add and sub operations, but low performance in multiply and divide operations between very large numbers compared with BigInteger class in Java11.

Environment

Works well in C++11.

Compiler	OS	Support
GCC-Clang 8.1.0	Windows	pass
MSVC-Clang 8.0.1	Windows	pass
MSVC 10.0	Windows	pass

Function

Support and Finished:

Unfinished but planned:

support BigDecimal

QuickStart

clone or download this project
include the header file (make sure at the same level as your source code file)
```
#include <BigInt.h>
```

create BigInt object

input long long int

long long int x = 123456789;
BigInt temp(x);

input string object

string pos_x = "123456789"; //or "+123456789", both means positive number
BigInt pos_temp(pos_x);
string neg_x = "-123456789"; //means negative number
BigInt neg_temp(neg_x);

operation For example, we want $[(x+1)^2 \times 123 \div y] \mod y$, which $x=-123456789, y=88888888$
```
BigInt x("-123456789");
BigInt y("88888888");
++x;
x = x.power(2);
x *= 123;
x /= y;
x %= y;
```

output

to string

BigInt temp("-123456789");
string temp_str = temp.to_string();

cout

BigInt temp("-123456789");
cout << temp;
terminal will show: -123456789

Reference

My work referenced:

Karatsuba in Wiki https://en.wikipedia.org/wiki/Karatsuba_algorithm (this page in zh has wrong in example codes)
An implementation of BigInteger for C++ https://github.com/panks/BigInteger

License