The single responsibility Principle of software Design (SRP) _ Design mode

Single Responsibility principle: there should be only one reason for a class to change (ASD).
I just learned to program, is to learn the C language introduction. C language is a process-oriented language, just beginning to get used to, to now write the program will also be oriented process thinking impact. When it comes to object-oriented programming (Java), it's natural to add a variety of functions to a class, and then write all kinds of code in a class. But the disadvantage of doing so is that if a class has too much responsibility, it is the equivalent of coupling those responsibilities together, and a change in responsibility may inhibit or alter the ability of other responsibilities. This coupling design can lead to fragile design, and when the change occurs, the design will suffer unexpected damage. If you write all the functions in the same class, the class is highly coupled, the code inside is inter-related, and if you want to change one of the codes, you'll probably be able to pull the whole body. Changing a place can affect many other places, causing a lot of trouble for later maintenance code and potentially causing a variety of bugs.
Much of what software design really does is to identify responsibilities and separate them from each other. Often when we write a program, if there are more than one motivation to change a class, then this class has more than one responsibility.