Page 30 of 62
SBasic User's Manual SBasic Version 2.7 Page 30
Printed: December 5, 1999
Note that it is legal (but not good practice) to modify the index
variable inside the loop.
Normally, the index variable increments by one each time control
reaches the bottom of the loop. You can change the value by which the
index variable increments with the STEP modifier.
Example:
for n = 1 to 10 step 2
a = a + n
next
Here, the variable N starts with a value of one, and increments by two
each time control reaches the NEXT statement. Thus, N takes on the
values 1, 3, 5, 7, 9, and 11. When N becomes 11 at the top of the
loop, control immediately passes to the statement following the NEXT
statement.
The SELECT statment marks the beginning of a SELECT-CASE control
structure. The SELECT-CASE structure allows your code to select one
option out of a list, based on the value of an argument, called the
selector. Only the CASE clause associated with the matching selector
value, if any, is executed.
The general format of a SELECT-CASE structure is:
select foo ' use value of FOO as selector
case 123 ' if FOO = 123...
. ' execute this code
. '
endcase ' end of case 1
case 456 ' if FOO = 456...
. ' execute this code
. '
endcase ' end of case 2
endselect ' end of select structure
This structure replaces the older ON-GOTO construct, and allows
creation of code that is easier to debug and maintain.
The SELECT-CASE structure supports variations for handling special
cases. For example:
select foo + 3*j ' use expression for selector
case 1 ' if selector = 1...
case n ' or N...
case 'X' ' or ASCII character X...
foo = n + 3 ' change FOO
endcase ' end of first case