How to read command line arguments in ALGOL?

ALGOL, an algorithmic language developed in the 1960's, does not directly support command line arguments. Unlike some more modern programming languages such as Java and Python, ALGOL does not have built-in features for directly accepting command line arguments upon program initiation.

However, while you cannot directly pass command line arguments into your ALGOL program, you can design your program in such a way that it can accept and process user input while the program is running. Due to the limitations of ALGOL, the user input will need to be manually inserted during the execution of the program, rather than as command line arguments that are input when calling the program from the command line.

Here is a simple way to collect and use user input during an ALGOL program's runtime:

Step 1: First, define a place in your code where you want to accept user input. This can be at the beginning of your program, or anywhere throughout where user input is needed.

Step 2: Utilize a BEGIN block to establish a scope for the input and associated tasks.

Step 3: Within this BEGIN block, define a variable that will hold the value input by the user. For instance, if you want to collect a string from the user, you could use the ALGOL keyword string to define your variable:

string userInput;

Step 4: Use the in keyword, in combination with ALGOL's read command, to gather input from the user and store it in your defined variable:

in('TTY:', userInput);

With the line of code above, the program will wait for the user to insert input via the terminal (or 'TTY:') and then store this input into the userInput variable.

Step 5: You can then use this variable userInput as you would use a command line argument in other languages, passing it to other functions or manipulating it as needed in your program.

This is not as efficient as using command line arguments like in more modern languages, but due to the age and design of ALGOL, it is one of the only ways to gather and utilize user input directly while a program is running.