20 lines
534 B
Plaintext
20 lines
534 B
Plaintext
REPEAT
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READ N$
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IF FN_isanumber(N$) THEN
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PRINT "'" N$ "' is a number"
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ELSE
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PRINT "'" N$ "' is NOT a number"
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ENDIF
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UNTIL N$ = "end"
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END
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DATA "PI", "0123", "-0123", "12.30", "-12.30", "123!", "0"
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DATA "0.0", ".123", "-.123", "12E3", "12E-3", "12+3", "end"
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DEF FN_isanumber(A$)
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ON ERROR LOCAL = FALSE
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IF EVAL("(" + A$ + ")") <> VAL(A$) THEN = FALSE
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IF VAL(A$) <> 0 THEN = TRUE
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IF LEFT$(A$,1) = "0" THEN = TRUE
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= FALSE
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