81 lines
1.2 KiB
Text
81 lines
1.2 KiB
Text
CHAR ARRAY digits="0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz!"
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INT FUNC MyMod(INT a,b)
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IF b>=0 THEN
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RETURN (a MOD b)
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FI
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RETURN (a-(b*(a/b)))
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PROC Encode(INT n,base CHAR ARRAY res)
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INT i,d,len
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CHAR tmp
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IF base<-63 OR base>-1 THEN Break() FI
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IF n=0 THEN SAssign(res,"0") FI
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len=0
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WHILE n#0
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DO
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d=MyMod(n,base)
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n==/base
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IF d<0 THEN
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n==+1
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d==-base
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FI
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len==+1
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res(len)=digits(d+1)
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OD
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res(0)=len
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FOR i=1 to len/2
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DO
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tmp=res(i)
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res(i)=res(len-i+1)
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res(len-i+1)=tmp
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OD
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RETURN
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BYTE FUNC Index(CHAR ARRAY s CHAR c)
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BYTE i
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FOR i=1 TO s(0)
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DO
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IF s(i)=c THEN RETURN (i) FI
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OD
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RETURN (0)
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INT FUNC Decode(CHAR ARRAY s INT base)
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INT res,b,i,pos
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IF base<-63 OR base>-1 THEN Break() FI
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IF s(0)=1 AND s(1)='0 THEN RETURN (0) FI
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res=0
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b=1
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pos=s(0)
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WHILE pos>=1
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DO
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i=Index(digits,s(pos))-1
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res==+i*b
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b==*base
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pos==-1
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OD
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RETURN (res)
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PROC Test(INT n,base)
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CHAR ARRAY s(20)
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INT v
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Encode(n,base,s)
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PrintF("%I encoded in base %I is %S%E",n,base,s)
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v=Decode(s,base)
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PrintF("%S decoded in base %I is %I%E%E",s,base,v)
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RETURN
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PROC Main()
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INT v
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Test(10,-2)
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Test(146,-3)
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Test(15,-10)
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Test(-568,-63)
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RETURN
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