Design principles

The two very important design principles are

1. Open close principle
2. Dependency Inversion Principle

Open close priciple :

This states that a design should be open for extension and closed for modification.

Design patterns

Gof design patterns

1. Creational patterns
2. Structural patterns
3. Behavioral patterns

Stock value

When PE ratio is high and you buy it, your risk profile is high.That indicates, in bear market it may come down without any support.

When PE ratio is lower and you buy, it says the stock is worth more than its current value, in bear market it may not come down drastically