LOOPS
RC BASIC has 3 types of loops: FOR, WHILE, and
DO.
The FOR loop repeats a block of code and increments a
counter each time it finishes the block between FOR and NEXT. When the
counter reaches a certain value the FOR LOOP stops.
For I = 1 To 5
Print I
Next
The above code will output the numbers 1 to 5 to the
console. Optionally you could use the STEP keyword to set the number that
the counter will increase by. Look at the following:
For I = 1 To 5 Step 2
Print I
Next
The above code will output the numbers 1, 3, and 5 to the
console. The STEP keyword increases I by 2 each time through the FOR
loop.
WHILE loops will execute a block of code while a certain
condition is true.
I = 0
While I < 5
Print I
I = I + 1
Wend
The above code will output the numbers 0 to 4. It
will not output the number 5 because if ( I < 5 ) is false the loop will
not repeat.
The DO loop is similar to the WHILE loop with an
exception. The WHILE loop checks for the loop condition at the start
of the loop but the DO loop checks for the loop condition at the end of the
loop. What this means is that a WHILE loop will never execute if the
condition is false at the start but the DO loop is guaranteed to execute at
least once before it checks if the condition was true or not.
The DO loop is also unique in that it has 3 different
forms. Here is the simplest form of the DO loop.
Do
Print "HELLO WORLD"
Loop
The code above will continue to output HELLO WORLD to the
console infinitely.
I = 0
Do
Print I
I = I + 1
Loop While I < 5
The above code will output the numbers 0 to 4 to the
console. This form of the DO loop will continue to loop while the loop
condition is true.
I = 0
Do
Print I
I = I + 1
Loop Until I = 5
The above code will output the numbers 0 to 4 to the
console. This form of the DO loop will continue to loop until the loop
condition is true.