This is a math library implemented in C++ (but mostly written in the style of C). It was created for my use on Project Euler problems, which require the use of very long numbers. In order to complete those problems, I needed a way to store numbers much larger than can be stored in a standard data type.
BigInt is a class that has a count of digits, and an array of digits. The math library is primarily operator overrides for use with BigInts, along with a few other functions. The method of storing BigInts is the most interesting thing about this class. Instead of storing them with the most significant bit (MSB) on the left and least significant bit (LSB) on the right, this stores the MSB on the right (at index digits-1 of the array) and the LSB on the left (at index 0 of the array). This allows for easily making the number larger (or smaller) without having to move the whole thing over.
The development of operator overrides for BigInts is an ongoing process. Many have already been implemented but could be made much more efficient. The goal of implementing all these operator overrides is to make the use of these BigInts as intuitive and readable as possible. The operators take BigInts on the left and int, long, string, or BigInt on the right.
The tests are contained within math.cpp. That file gives a pretty good example of usage of the library. The tests are fairly thorough with testing, but extensive testing of different numbers could be added as an improvement.
This math library can be downloaded from Github and stored locally. The mathlib.h file can then be referenced in a .cpp file as demonstrated in math.cpp. The library can also be used in a C file, but the g++ compiler must be used since classes are not valid in the gcc compiler.
Feel free to use this repo, and to fork it if you want to adapt it for some other purpose. I welcome contributions. Please create a branch/issue/pull request! Please comment any code that you wish to add, or I probably won't review it...