Your First COBOL Program - Hello World

Writing a “Hello, World!” program is a rite of passage for many developers when they begin learning a new programming language. In this guide, we’ll walk you through the steps to create, compile, and execute your first COBOL program. Get ready to become a COBOL programmer!

Step 1: Setting Up Your Environment

Before we dive into coding, make sure you have a COBOL compiler installed on your machine. There are several options available, both free and commercial. Some popular choices include:

GnuCOBOL: An open-source COBOL compiler that translates COBOL code into C and then uses GCC to compile it.
Micro Focus Visual COBOL: A commercial package that provides a rich IDE for COBOL development.
IBM Enterprise COBOL: A powerful IDE used widely in enterprise settings.

You can choose the one that fits your needs, but for the purposes of this tutorial, we will use GnuCOBOL, as it's freely available and works on multiple platforms.

Installing GnuCOBOL

On Linux: Open your terminal and run:
```
sudo apt-get install gnucobol
```
On macOS: If you have Homebrew installed, you can run:
```
brew install gnu-cobol
```
On Windows: You can download the GnuCOBOL installer from the GnuCOBOL website or use Cygwin.

Once you’ve installed the compiler, you’re ready to start coding!

Step 2: Writing Your Hello World Program

Now, let’s create your first COBOL program. COBOL programs are structured but fairly straightforward. Follow these steps:

Open your favorite text editor (such as Notepad on Windows, nano or vim on Linux, or TextEdit on macOS).
Create a new file named hello.cob. You can use a command like the following in your terminal:
```
touch hello.cob
```
Write the following code in the hello.cob file:

       IDENTIFICATION DIVISION.
       PROGRAM-ID. HelloWorld.

       ENVIRONMENT DIVISION.

       DATA DIVISION.

       WORKING-STORAGE SECTION.
       01  WS-MESSAGE   PIC X(20) VALUE 'Hello, World!'.

       PROCEDURE DIVISION.
       DISPLAY WS-MESSAGE.
       STOP RUN.

Understanding the Code

Let’s break down this code so you grasp how COBOL works:

IDENTIFICATION DIVISION: This section declares basic information about the program, including its name.
PROGRAM-ID: The name of your program; here, it's HelloWorld.
ENVIRONMENT DIVISION: This is where you define the environment in which your program runs. For this simple program, we don’t need to specify anything, so we leave it mostly empty.
DATA DIVISION: This section is for defining variables. We declare WS-MESSAGE as a string of 20 characters with the initial value 'Hello, World!'.
PROCEDURE DIVISION: This is where the logic of your program goes. We use the DISPLAY statement to print the message to the console and STOP RUN to finish the program.

Step 3: Compiling the Program

Now that your code is ready, it’s time to compile it. Open your terminal and navigate to the directory where you saved hello.cob:

cd path/to/your/directory

Then compile your program using GnuCOBOL with the following command:

cobc -x hello.cob

This command tells the GnuCOBOL compiler to create an executable program. If everything goes well, you should find an executable named hello (or hello.exe on Windows) in the same directory.

Step 4: Running the Program

You are now ready to run your first COBOL program! Just type the following command in your terminal:

./hello

(Use hello.exe if you are on Windows.) If everything is set up correctly, you should see the output:

Hello, World!

Congratulations! You’ve just written and executed your first COBOL program!

Step 5: Troubleshooting Common Issues

While everything might work smoothly, you could run into issues. Here are some common problems and how to address them:

Compilation Errors

Syntax Errors: Check the syntax carefully; COBOL is sensitive to punctuation and formatting. Ensure each line follows COBOL rules.
Missing Sections: Ensure you include the necessary divisions: IDENTIFICATION, ENVIRONMENT, DATA, and PROCEDURE.

Execution Errors

Executable Not Found: If the executable wasn’t created, verify your compile command’s output for any errors.
Permission Issues: Ensure you have the permission to execute the file. If you get a permission denied error, run:
```
chmod +x hello
```

Step 6: Next Steps After Hello World

With your first program successfully running, you might wonder where to go from here. Here are a few next steps to continue your COBOL journey:

Explore Data Types: Learn about different data types in COBOL, such as numeric, alphanumeric, and numeric edited.
Control Structures: Get familiar with conditional statements (IF) and loops (PERFORM).
File Handling: Discover how COBOL manages files, which is crucial in many business applications.
Advanced Topics: Investigate advanced COBOL features such as Object-Oriented COBOL and integration with modern technologies.

Conclusion

You’ve successfully written, compiled, and executed a simple "Hello World" program in COBOL! This fundamental skill sets the stage for learning more complex programming concepts. Remember that programming is an iterative process, and practice will solidify your understanding. So keep coding, exploring, and pushing the boundaries of what you can achieve with COBOL!

Happy coding!

Programming - COBOL