51 lines
2.5 KiB
Rexx
51 lines
2.5 KiB
Rexx
/*REXX program computes and displays various (integer) exponentiations. */
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say center('digits='digits(), 79, "─")
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say 'iPow(17, 65) is:'
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say iPow(17, 65)
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say
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say 'iPow(0, -3) is:'
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say iPow(0, -3)
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say
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say 'iPow(8, 0) is:'
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say iPow(8, 0)
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say
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numeric digits 12; say center('digits='digits(), 79, "─")
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say 'iPow(2, -10) is:'
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say iPow(2, -10)
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say
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numeric digits 30; say center('digits='digits(), 79, "─")
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say 'iPow(-3.1415926535897932384626433, 3) is:'
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say iPow(-3.1415926535897932384626433, 3)
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say
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numeric digits 60; say center('digits='digits(), 79, "─")
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say 'iPow(5, 70) is:'
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say iPow(5, 70)
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say
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numeric digits 100; say center('digits='digits(), 79, "─")
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say 'iPow(17, 65) is:'
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say iPow(17, 65)
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say
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numeric digits 1000; say center('digits='digits(), 79, "─")
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say 'iPow(2, 1000) is:'
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say iPow(2, 1000)
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exit /*stick a fork in it, we're all done. */
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/*──────────────────────────────────────────────────────────────────────────────────────*/
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errMsg: say; say '***error***'; say; say arg(1); say; say; exit 13
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/*──────────────────────────────────────────────────────────────────────────────────────*/
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iPow: procedure; parse arg x 1 _,p; #args= arg() /*_: is a copy of X. */
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if #args<2 then call errMsg "not enough arguments specified"
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if #args>2 then call errMsg "too many arguments specified"
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if \datatype(x, 'N') then call errMsg "1st arg isn't numeric:" x
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if \datatype(p, 'W') then call errMsg "2nd arg isn't an integer:" p
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if p=0 then return 1 /*handle powers of zero. */
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if x=0 | x=1 then return x /*handle special cases. */
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do abs(p) - 1; _= _ * x; end /*perform exponentiation */
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if p<0 then _= 1 / _ /*process its reciprocal.*/
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return _
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