Loops

Sometimes you may want to repeat a sequence of statements. Ultra Fractal provides two constructs 

to do this: the while loop and the repeat loop. Here is the syntax:

while 

endwhile

repeat

until 

The while loop repeats the statements as long as the boolean expression is true. If the boolean 

expression is or becomes false, the statements are never or no longer executed. The repeat loop, 

however, repeats the statements until the boolean expression becomes true. This means that the 

statements are always executed at least once.

If you want the statements to be executed at least once, use the repeat loop. Otherwise, use the 

while loop.

Here is an example that calculates x = n! (defined as x = 1*2*3*...*(n 2)*(n 1)*n), first using a 

while loop, and then using a repeat loop:

int 

n = 

23   

; or another value

float 

x = 

1  

; float because 23! is very large

while 

(n > 

1

)

  x = x * n

  n = n   

1

endwhile

int 

n = 

23

float 

x = 

1

if 

n > 

1

repeat

x = x * n

    n = n   

1

until 

n == 

1

endif

Obviously, the while loop is better suited to calculate the factorial of a number, but in other cases 

the repeat loop may be better.

As with if statements, loops may be nested as much as you want.

Next: 

Transformations

280