Commodore VIC-20 - Page 40

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EXAMPLE 1:
100 INPUT A
110 INPUTS, C, D
120 INPUT "PROMPT11; E
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This program will fill the entire screen with Zs, including the
bottom right corner, and then freeze. The IF in tine 120 checks for
both X = 23 and Y = 22 being true, or else the program just drops
through to line 130. When the conditions aretrue, the VIC PRINTS a
cursor left and an insert.
By the way, this really is a trick to PRINT in the lower right earner
in the screen without forcing the screen to scroll up a line. This is
because you never really PRINT in that position, you insert in the
position before that, which pushes the character into position.
For those of you using cartridges that add extra commands to
BASIC, like "Super Expander" and ''Programmers Aid," make sure
thai you put a colon between the word THEN and one of the exira
commands.
EXAMPLE 4;
100 IF X = 4 THEN : GRAPHIC 4
INPUT |
Format: Abbreviation: Screen Display:
INPUT ["prompt";] None None
variable
This is a statement that lets the person running the program
"feed" irrformation into the computer. When executed, this
statement PRINTS a question mark (?) on the screen, and positions
the cursor 2 spaces to the right of the question mark, Now the
computer waits, cursor blinking, for the operator to type in the
answer and press the RETURN key.
The word INPUT may be followed by any text contained in quote
marks O- This text is PRlNTed on the screen, lollowed by the
question mark.
After the text comes the name of one or more variables
separated by commas. This variable is where the computer stores
the information that the operator types. The variable can be any
legal variable name, and you can have several different variable
names, each for a different input.
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