FORV

Contents


"For" is used to make variable assignment loops.

For file read loops, refer to the instruction documentation marked For(file)).

 

Syntax

SYNTAX 1
For variable_num  = value_init To value_end [ Step step ]
 ..... instructions
Next [ variable_num ]
SYNTAX 2
For variable  = list_values
 ..... instructions
Next [ variable ]

 

Parameters

Element

Description

Restrictions

variable_num

numerical type nom_de_variable containing the value of the loop, which changes from 'value_init' by 'step' increments.

None.

value_init

Initial numerical value of the variable.

None.

value_end

Final numerical value of the variable.

None.

step

Increment added to the variable with each iteration (1 by default).

None.

variable

nom_de_variable whose value will take each of the values of the list in succession.

None.

list_values

List of expressions separated by the character ','.

The expressions are the same type as the variable.

 

Examples

   For I = 1 To 13 Step 2.5 : Infbox num$(I) : Next I : Infbox "FIN="-num$(I)   
   # displays : 1 3.5 6 8.5 11 FIN=13.5
   For I = 15 To 12 : Infbox num$(I) : Next I : Infbox "FIN="-num$(I)
   # displays : FIN=15
   For I = 15 To 11 Step -1 : Infbox I : Next I : Infbox "FIN="-num$(I)
   # displays : 15 14 13 12 11 FIN=10
   For  CHN="A","EF","X","ZZZ" : Infbox CHN : Next CHN : Infbox "FIN="-CHN  
   # displays: A EF X ZZZ FIN=ZZZ

 

Description and comments

SYNTAXES 1 AND 2

"For" is used to make loops in which a variable takes a set of values. The value of the variable must not be modified within the loop.

The only ways of leaving a For loop are:

·         to reach the limits (syntax 1),

·         to have exhausted all values (syntax 2),

·         to use Break, interrupting the loop.

Value of the loop variable on leaving the loop:

·         the first value outside the limits (syntax 1),

·         the last value on the list (syntax 2).

Number of iterations:

If (value_end - value_init) does not have the same sign as the step, the loop will never be executed, and the value on leaving the loop will be the initial value.

 

Comments

In syntax 1, the loop variable, its initial and final values and the step are not reevaluated in the loop.

 

Associated errors

Error

Description

ERMODE (10) :

- variable_num, value_init, value_end, or the step are not numerical (syntax 1).
- A value on the list is of a type incompatible with the variable type (syntax 2).

ERLOOP (41)

The step value is null.

 

Associated key words

FORF - BREAK - WHILE - REPEAT


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