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Lesson 4 Course project
Objective General specifications of the C++ Course Project

General specifications of the C++ Course Project

The skills you gain in this course will be put to the test in the course project. You will be building a life simulation program that prints out a grid of randomly generated cells that become alive, stay alive, or become empty depending on a set of rules. The program uses a dynamically generated two-dimensional array to store information about and display the cells. Each cell on the "life board" is either empty or alive. There are a number of ways to display whether a cell is alive or empty. A common way is to have 1's represent cells that are alive and 0's represent empty cells:
0 0 0 0 0 0 0 0 0 0
0 1 1 0 0 1 0 1 0 0
0 0 0 1 0 1 0 0 1 0
0 1 1 0 1 0 1 0 0 0
0 0 1 0 1 0 0 0 0 0
0 1 0 1 0 1 1 1 0 0
0 1 1 1 1 1 0 0 0 0
0 1 0 1 0 1 0 0 0 0
0 0 0 0 1 1 1 1 0 0
0 0 0 0 0 0 0 0 0 0

At each cycle, a cell either becomes alive, stays alive, or becomes empty depending on how many neighbors it has. By displaying the board at each cycle or at periodic times during the lifetime of the board, you can see how the pattern of life varies.
While this program is the final project for this course, it serves as the basis for the course projects in the next two courses in the C++ for C Programmers series, culminating in a predator/prey simulation in the final course of the series.

Why the main function has a return type int

In C++, the `main` function has a return type of `int` primarily to communicate the exit status of the program to the operating system. The return value serves as a status code where `0` typically indicates successful execution, and non-zero values indicate different types of errors. This convention is widely used in various operating systems and programming environments.
Here are a few reasons why the return type is `int` rather than `double` or `string`:
  1. Convention and Portability: The use of an integer as a return type from `main` is a convention that dates back to early C standards, adopted in C++ for compatibility and portability between different operating systems. This convention allows programs to communicate their status in a simple, standardized way that is understood across various platforms.
  2. Simplicity and Efficiency: Using an integer provides a simple and efficient means of returning the program's status. It avoids the complexities and overhead associated with managing more complex types like `double` or `string`. For example, returning a `string` would involve dynamic memory allocation and deallocation, which is unnecessary for indicating exit status.
  3. Limited Interpretation of Double and String: Using `double` or `string` as a return type could complicate the interpretation of the exit status. The precision of a `double` and the variable length of a `string` do not provide clear advantages over a simple integer. Moreover, operating systems expect an integer status code, and using other types would lead to issues in how these return values are interpreted by system tools that expect an integer exit code.
  4. Standard Compliance: The C++ standard specifies that the `main` function should return an `int`. This standardization ensures that all C++ programs have a consistent entry and exit point, simplifying the compiler's job and ensuring that programs behave predictably across different environments.

Therefore, the choice of `int` as the return type for the `main` function in C++ is driven by the need for a straightforward, standardized method of reporting the program's exit status to the operating system.

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