[FIX] Pre-existing algorithms do not fit the contribution guidelines

### Detailed description

Times change

so does the development of algorithms and documentation

Some of the older algorithms existing in this repository do not fit the [contribution guidelines](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/CONTRIBUTING.md). A short list of examples: - [Armstrong number](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/math/armstrong_number.cpp) - [binary exponent](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/math/binary_exponent.cpp) - [check prime](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/math/check_prime.cpp) - [complex numbers](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/math/complex_numbers.cpp) - [square root double](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/math/sqrt_double.cpp) ### Context Educating new developers on coding standards is a major priority; As the industry today relies heavily on documentation; If you were to ask any API developer/user on what the most important part of their development and use it will always be: - Code quality - documentation having a fast and performant algorithm is good but whats the point if you cant understand how it works or even why it works. I think it is in the best interest of us to document our algorithms. As i consider all algorithms must be: - beautiful - understandable - educational ### Possible implementation _No response_ ### Additional information Others in the past have made major changes like this to this repository and i think its time for us to do the same. to keep the torch moving. An homage to @kvedala for their part in trying to standardize this repository #805