[−][src]Module basic::__Chapter_2::FOR
FOR <variable>=<x> TO <y> [STEP <z>]
Where x, y, and z are expressions.
Purpose
Used with NEXT
to repeat execution of statements
while iterating over a sequence of numbers.
Remarks
If we wanted the numbers 1,3,5,7 we would write FOR I=1 TO 7 STEP 2
.
On the first iteration, 1 will be assigned to variable I.
Statements execute until a NEXT
statement.
On subsequent iterations, the variable I gets 2 added to it.
If the result exceeds 7 the loop breaks.
Otherwise the statements get executed again.
The first iteration will evaluate x, then y, then z. Newer versions of BASIC evaluate z first.
The first iteration always executes even if starting past the end. Newer versions of BASIC may skip the first iteration.
Example 1
10 FOR I=1 TO 7 STEP 2
20 PRINT "HELLO WORLD";i
30 NEXT I
RUN
HELLO WORLD 1
HELLO WORLD 3
HELLO WORLD 5
HELLO WORLD 7
Example 2
10 FOR X=1 TO 2
20 FOR Y=5 TO 6
30 PRINT X;Y
40 NEXT Y,X
RUN
1 5
1 6
2 5
2 6