Entry

BBCBASIC: Program: Control structure: Loop: How to possibly quit a REPEAT UNTIL control structure?

Jan 28th, 2006 12:42
Knud van Eeden,

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--- Knud van Eeden --- 28 January 2021 - 05:36 pm --------------------
BBCBASIC: Program: Control structure: Loop: How to possibly quit a 
REPEAT UNTIL control structure?
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A general construct to quit a 'REPEAT UNTIL' loop could
be the following:
Steps: Overview:
 1. -Create a common variable to test if you have to stop
     when arriving at the UNTIL and set it to FALSE
      stopB% = FALSE
 2. -Create a separate Boolean variable for all the possible
     breakpoints and set them to FALSE
      stop1B% = FALSE
      stop2B% = FALSE
      ...
      stopLastB% = FALSE
 3. -Inside the REPEAT UNTIL loop set the corresponding Boolean
     variable to TRUE if you want to quit the loop
      e.g.
       stop2B% = TRUE
 4. -If any of this Boolean variables is TRUE, you want to quit
     the loop
      stopB% = stop1B% OR stop2B% OR stop3B% OR ... OR stopLastB%
     making stopB% TRUE
 5. -If stopB% is TRUE, you quit the loop
===
--- cut here: begin --------------------------------------------------
stopB% = FALSE
:
stop1B% = FALSE
stop2B% = FALSE
...
stopLastB% = FALSE
:
REPEAT
 do something 1 and let stop1B% = TRUE
 do something 2 and let stop2B% = TRUE
 ...
 do something last and let stoplastB% = TRUE
 ...
 stopB% = stop1B% OR stop2B% OR stop3B% OR ... OR stopLastB%
UNTIL stopB%
:
END
--- cut here: end ----------------------------------------------------
===
E.g.
--- cut here: begin --------------------------------------------------
stopB% = FALSE
:
stop1B% = FALSE
:
I% = 1 - 1
REPEAT
 I% = I% + 1
 PRINT I%
 IF I% >= 2 THEN stop1B% = TRUE
 stopB% = stop1B%
UNTIL stopB%
END
--- cut here: end ----------------------------------------------------
===
E.g.
--- cut here: begin --------------------------------------------------
stopB% = FALSE
:
stop1B% = FALSE
stop2B% = FALSE
:
I% = 1 - 1
J% = 1 - 1
REPEAT
 I% = I% + 1
 J% = J% + 1
 PRINT I%, J%
 IF I% >= 2 THEN stop1B% = TRUE
 IF J% >= 2 THEN stop2B% = TRUE
 stopB% = stop1B% OR stop2B%
UNTIL stopB%
END
--- cut here: end ----------------------------------------------------
===
E.g.
--- cut here: begin --------------------------------------------------
stopB% = FALSE
:
stop1B% = FALSE
stop2B% = FALSE
stop3B% = FALSE
:
I% = 1 - 1
J% = 1 - 1
K% = 1 - 1
REPEAT
 I% = I% + 1
 J% = J% + 1
 K% = K% + 1
 PRINT I%, J%, K%
 IF I% >= 2 THEN stop1B% = TRUE
 IF J% >= 2 THEN stop2B% = TRUE
 IF K% >= 3 THEN stop3B% = TRUE
 stopB% = stop1B% OR stop2B% OR stop3B%
UNTIL stopB%
END
--- cut here: end ----------------------------------------------------
===
E.g.
--- cut here: begin --------------------------------------------------
stopB% = FALSE
:
stop1B% = FALSE
stop2B% = FALSE
stop3B% = FALSE
stop4B% = FALSE
:
REPEAT
 PRINT; "command = ";
 INPUT s$
 IF s$ = "break1" THEN stop1B% = TRUE
 IF s$ = "break2" THEN stop2B% = TRUE
 IF s$ = "break3" THEN stop3B% = TRUE
 IF s$ = "quit" THEN stop4B% = TRUE
 stopB% = stop1B% OR stop2B% OR stop3B% OR stop4B%
UNTIL stopB%
END
--- cut here: end ----------------------------------------------------
===
E.g.
--- cut here: begin --------------------------------------------------
stopB% = FALSE
:
stop1B% = FALSE
stop2B% = FALSE
stop3B% = FALSE
stop4B% = FALSE
:
REPEAT
 PRINT; "command = ";
 INPUT s$
 IF s$ = "break1" THEN stop1B% = TRUE
 IF s$ = "break2" THEN stop2B% = TRUE
 IF s$ = "break3" THEN stop3B% = TRUE
 IF s$ = "quit" THEN stop4B% = TRUE
 stopB% = stopB% OR stop1B%
 stopB% = stopB% OR stop2B%
 stopB% = stopB% OR stop3B%
 stopB% = stopB% OR stop4B%
UNTIL stopB%
END
--- cut here: end ----------------------------------------------------
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Internet: see also:
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