My Data Structures and Algorithmes course final project.
The main idea of project was to create a calculator that can evaulate operations on big numbers, like 50 digit numbers.
This calculator also has a cursor which lets you to manage the string before evaulation.
For evaulation we use the post-fix format which we need to build from an in-fix string.
Since calculating big numbers needs a large memory space, we decrease our results by moding them by 10^9 + 7.
Also we use a hash-map to store the results, thus in case of evaulation old strings, we just get them from our cache.