14 lines
1.1 KiB
Rexx
14 lines
1.1 KiB
Rexx
/*REXX program demonstrates handling an exception (negative #); catching is via a label.*/
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do j=9 by -5
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say 'the square root of ' j " is " sqrt(j)
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end /*j*/
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exit /*stick a fork in it, we're all done. */
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/*──────────────────────────────────────────────────────────────────────────────────────*/
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sqrt: procedure; parse arg x; if x=0 then return 0; d=digits(); h=d+6; m.=9
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numeric digits; numeric form; if x<0 then signal .sqrtNeg
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parse value format(x, 2, 1, , 0) 'E0' with g 'E' _ .; g=g * .5'e'_ % 2
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do j=0 while h>9; m.j=h; h=h%2 + 1; end /*j*/
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do k=j+5 to 0 by -1; numeric digits m.k; g=(g+x/g) * .5; end /*k*/
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numeric digits d; return g/1
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.sqrtNeg: say 'illegal SQRT argument (argument is negative):' x; exit 13
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