Write a complete C++ program and create 13 classes that form a class tree as shown in Figure 1. Every class has only one no-argument constructor, no property, and no regular method. Inside the no-argument constructor, there is only one output statement to print "This is the constructor of xxx class". Add a line break at the end of the printout. There is no need to split the code due to the simplicity of all classes. Place all 13 classes and the main function should be coded in a single source file Living Thing Animal Plant Fish amma Tree ardineBass Cat Chestnu Ti In the main function, create one object for each leaf classes, .e. classes Sardine, Bass, Tiger, Lion, Figure I After successful debugging and running the project, carefully observe the printout and write your own explanation to a text file named "readme.txt". Place this file in the source file folder of your project. The file should have at least 80 words. The file should clearly explain: 1) how constructors are involved in inheritance, 2) the time sequence of the execution of related constructors in terms of the class tree