The for statement implements an iterative loop and requires you to specify the number of iterations. The syntax of the for statement is:

for counter = initial_value to final_value [step step_value]
  statement_list
next counter

counter is a variable which increments with each iteration of the loop. Before the first iteration, counter is set to initial_value and will increment until it reaches final_value. final_value will be recalculated each time the loop is reentered.
This way number of loop iterations can be changed inside the loop by changing final_value. With each iteration, statement_list will be executed.

initial_value and final_value should be expressions compatible with counter; statement_list may be consisted of statements that don't change the value of the counter.

Note that the parameter step_value may be negative, allowing you to create a countdown.

If final_value is a complex expression whose value can not be calculated in compile time and number of loop iterations is not to be changed inside the loop by the means of final_value, it should be calculated outside the for statement and result should be passed as for statement's final_value. statement_list is a list of statements that do not change the value of counter.

Here is an example of calculating scalar product of two vectors, a and b, of length 10, using the for statement:

s = 0
for i = 0 to 9
  s = s + a[i] * b[i]
next i

Endless Loop

The for statement results in an endless loop if final_value equals or exceeds the range of the counter’s type.

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