The BASIC programming language

Writing single line programs is kind of limited, so let's see how to write programs with multiple lines.

To write our program we first need to enter the programming mode, to do this simply press the mode key until the PRO indicator is displayed above the screen. This modes gives us a "text editor" like interface that will make writing long programs easier.

TODO: add graphics

Now the computer is ready to accept our program, lets start with the classical Hello, World! program. The program is introduced line by line, so first we introduce the following input.

10 PRINT "HELLO, WORLD!"

When you are done introducing the line, press the enter key to accept it. The first number in the line is the line number, it is used to reference the line in the program, and is mandatory. After the line number we have the statement, in this case PRINT, which prints the string that follows it, in this case "HELLO, WORLD!".

Now we can run the program, to do this, press the MODE key until the RUN prompt is displayed above the screen. Then press enter the following command.

RUN

The program will run and display the HELLO, WORLD! message on the screen.

Let's add a second line to our program, to do this return to the PRO mode and write:

20 PRINT "GOODBYE, WORLD!"

Running the program again will show the two lines, one after another. Let's say we want to output something between the two lines, we can simply add a new line in PRO mode, between the two existing lines.

15 PRINT "I'M A COMPUTOR!"

Running wil yield the expected output, but oops we made a typo, to fix it we can go again into PRO mode and use the list command

LIST 15

This will let us edit the line, and fix the typo, to do this point the cursor to the incorrect character by using the left and right keys, then simply press the character you want to replace it with, in this case E.

15 PRINT "I'M A COMPUTER!"