Until now our programming has been limited to running through the code once, and then the program stops functioning. This is clearly not suitable for a robot, which must be able to follow it's commands continuously for the length of time it is switched on. To do this we use loops.

We also want our robots to make decisions based on data from its sensors, for this we need conditional statements. Loops themselves contain conditional statements in order to tell them when to run and how long to continue.

There are several different loop commands, letting us control the function of the robot in a variety of ways.

Do Loops:

The simple Do loop can be used to enclose your whole program, when it reaches the end of the code it returns to the beginning and starts again. We can apply this to our program used in the introduction.

Sub main()
Dim answer As string
Dim answerI As integer

Do 'start of loop
 
answerI = 5*5
answer=Cstr(answerI)
debug.print "The answer is "; answer
 
Loop ' end of loop
End Sub
 

As you will see when you run this program, the statement is no longer displayed once, but continues to print as long as the program runs (you should press the reset button to stop it)

Now for something slightly more useful. We can add a conditional statement to the do loop by using a ' while ' statement. This lets us tell the Robocore when to stop looping.

Sub main()
 
Dim answerI As integer
Dim answer As string
Dim i As integer
i=0
 
Do While (i < 10)
answerI = 5*5
answer=Cstr(answerI)
debug.print "The answer is "; answer
i=i+1
loop
 
End Sub
 
Using the conditional statement ' while ' and a new integer variable i we have made the Robocore loop only 10 times (note that as 10 is not less than 10 the program will stop after the I = 9 loop)

For Loop:

We can set up the same loop using the for statement remove the Do while, Loop and i=i+1 lines and replace them with:

Do While For I = 1 to 10 Step 1

Loop Next

The loop runs from 1 to 10 stepping up 1 each loop, this removes the need for the line I=I+1.

Run the program to check that you have got it right.

Now for something a little more complex, instead of just doing one sum, we can automate the Robocore to do 10 different sums for us by changing the equation to

AnswerI = I*5

Now the Robocore takes the number of loops completed and multiplies it by five. When you run this program you should now get the answers 5,10,15 up to 50.

If Statement:

We can run a conditional statement without using a loop with an if statement. These are used as follows

Const switch as Byte = 5
Sub Main()
Do
 
if (GetPin(switch)=1) then
debug.print"switch pressed"
call sleep(0.15)
end if

Loop
End Sub
 

The best way to learn is to experiment, make your own program with what you've learnt and you'll soon feel more confident