What is class diagram?
A class diagram is a type of diagram and part of a uniform modeling language (UML) that defines and provides the overview and structure of a system with regard to classes, attributes and methods as well as the relationships between different classes.
It is used to illustrate and create a functional diagram of the system classes and serves as a system development resource within the software development lifecycle.
A class diagram is primarily designed for developers to provide the conceptual model and architecture of the system being developed. As a rule, a class diagram consists of more than one class or all classes created for a system.
It is a kind of structural diagram and resembles a flowchart with three main parts outlined in rectangular boxes. The first or upper part indicates the class name, the second or middle part indicates the attributes of that class, and the third or lower part lists the methods or operations that this class can perform.