After graduating, you are hired as a computer engineer for Synchworks Company, 
which is established newly, to develop a simple concurrent accounting application. 
For this application, you are wanted to implement a consistent solution for 
distributing the equity of the company to its shareholders.

The equity policy of the company is as follows:

The starting equity of the company is $0.
There exists 20 shareholders and each of them withdraws $2 every single day (iteration).
When current equity is equal to or less than $10, shareholders are not allowed to withdraw their shares.
The owner of the company invests $50 for each 5 days.

In your program, create two thread functions for the investor and shareholders which operates continuously. 
Use condition variables in order to control current equity.