RosettaCodeData/Task/Fibonacci-sequence/ANSI-BASIC/fibonacci-sequence.basic
2026-04-30 12:34:36 -04:00

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100 REM Fibonacci sequence
110 DECLARE EXTERNAL FUNCTION Fib
120 INPUT PROMPT "Enter n for fib(n): ": N
130 PRINT Fib(N)
140 END
150 REM ***
160 EXTERNAL FUNCTION Fib(N)
170 IF N = 0 THEN
180 LET Fib = 0
190 ELSEIF N = 1 THEN
200 LET Fib = 1
210 ELSE
220 LET Prev = 0
230 LET Curr = 1
240 FOR I = 2 TO N
250 LET T = Curr
260 LET Curr = Prev + Curr
270 LET Prev = T
280 NEXT I
290 LET Fib = Curr
300 END IF
310 END FUNCTION