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whilewhileWhileWhile (Operator)


whilewhileWhileWhile — Starts a loop block that is executed as long as the condition is true.


while( : : Condition : )

Herror while(const Hlong Condition)

Herror T_while(const Htuple Condition)

void While(const HTuple& Condition)

static void HOperatorSet.While(HTuple condition)


whilewhileWhileWhileWhile executes the loop body up to the corresponding endwhileendwhileEndwhileEndwhileEndwhile statement as long as the ConditionConditionConditionConditioncondition parameter evaluates to 'true'"true""true""true""true" (or a number not equal 0).

If the condition evaluates to 'false'"false""false""false""false" (0) the program is continued after the corresponding endwhileendwhileEndwhileEndwhileEndwhile statement.


ConditionConditionConditionConditioncondition (input_control)  integer HTupleHTupleHtuple (integer) (int / long) (Hlong) (Hlong)

Condition for loop.

Example (HDevelop)

dev_update_window ('off')
dev_close_window ()
dev_open_window (0, 0, 512, 512, 'black', WindowID)
read_image (Image, 'particle')
dev_display (Image)
stop ()
threshold (Image, Large, 110, 255)
dilation_circle (Large, LargeDilation, 7.5)
dev_display (Image)
dev_set_draw ('margin')
dev_set_line_width (3)
dev_set_color ('green')
dev_display (LargeDilation)
dev_set_draw ('fill')
stop ()
complement (LargeDilation, NotLarge)
reduce_domain (Image, NotLarge, ParticlesRed)
mean_image (ParticlesRed, Mean, 31, 31)
dyn_threshold (ParticlesRed, Mean, SmallRaw, 3, 'light')
opening_circle (SmallRaw, Small, 2.5)
connection (Small, SmallConnection)
dev_display (Image)
dev_set_colored (12)
dev_display (SmallConnection)
stop ()
dev_set_color ('green')
dev_display (Image)
dev_display (SmallConnection)
Button := 1
while (Button == 1)
  dev_set_color ('green')
  get_mbutton (WindowID, Row, Column, Button)
  dev_display (Image)
  dev_display (SmallConnection)
  dev_set_color ('red')
  select_region_point (SmallConnection, SmallSingle, Row, Column)
  dev_display (SmallSingle)
  NumSingle := |SmallSingle|
  if (NumSingle == 1)
    intensity (SmallSingle, Image, MeanGray, DeviationGray)
    area_center (SmallSingle, Area, Row, Column)
    dev_set_color ('yellow')
    set_tposition (WindowID, Row, Column)
    write_string (WindowID, 'Area='+Area+', Int='+MeanGray)
dev_set_line_width (1)
dev_update_window ('on')


If the values of the specified parameters are correct, whilewhileWhileWhileWhile (as operator) returns 2 (H_MSG_TRUE). Otherwise an exception is raised and an error code returned.


forforForForFor, untiluntilUntilUntilUntil

See also

repeatrepeatRepeatRepeatRepeat, breakbreakBreakBreakBreak, continuecontinueContinueContinueContinue, ififIfIfIf, elseifelseifElseifElseifElseif, elseelseElseElseElse