Data commit

Task/Negative-base-numbers/Action-/negative-base-numbers.action

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