Commodore VIC-20 - Page 364

350 The VIC 20 User Guide
If an unconditional branch is one of many statements following THEN,
the branch must be the last statement on the line, and it must have "GOTO
line" format.
If the unconditional branch is not the last statement on the line,
then statements following the unconditional branch can never
be executed.
The following statements cannot appear in an immediate mode IF-
THEN statement: DATA, GET, GET#, INPUT, INPUT#, REM, RETURN,
END, STOP, WAIT.
If a line number is specified, or any statement containing a line number,
there must
be a corresponding statement with that line number in the
current stored program.
The CO NT and DATA statements cannot appear in a program mode
IF-THEN statement.
If a FOR-NEXT loop follows the THEN, the loop
must be completely contained on the IF-THEN line. Additional IF-THEN
statements may appear following the THEN as long
as they are completely
contained on the original IF-THEN line. However, Boolean connectors are
preferred to nested IF-THEN statements.
For example, the two statements
below are equivalent, but the second
is preferred.
18 IF AS="X" THEN IF '1112 THEN IF C)D THEN 50
10 IF AS="X" AND )1"2 AND C)D THEN 50
Example:
4ee IF X>Y THEN A=l
500 IF M+l THEN AO=4.5 GOSUB 1000
INITIAUZE
You can use PRINT# to initialize a diskette before performing any
operation on it.
Format:
PRINT#file, "[INITIALIZE][ dr]"
The diskette in drive dr is initialized. If the dr parameter is not present,
the diskette in drive 0 will
be initialized. You do not need to initialize a
diskette after preparing it; the preparation process also initializes the
diskette.
Example:
OPEN 1.8,15
Open the diskette command channel