PRINT
PRINT "筆算＿平方根"
PRINT
INPUT PROMPT "答えとなる２〜４桁の数？ ":Xx
PRINT
DIM A$(10),Aa(10),B(10),Q(10),W(10)
MAT Aa=ZER
LET x=Xx^2
LET z=LEN(y$)
LET y$=STR$(x)
LET z=LEN(y$)
IF z/2=INT(z/2) THEN
   FOR i=1 TO z/2
      LET A$(i)=y$(2*i-1:2*i)
      LET Aa(i)=VAL(A$(i))
   NEXT i
ELSE
   LET A$(1)=y$(1:1)
   LET Aa(1)=VAL(A$(1))
   FOR i=2 TO INT((z+1)/2)
      LET A$(i)=y$(2*i-2:2*i-1)
      LET Aa(i)=VAL(A$(i))
   NEXT i
END IF
FOR i=9 TO 1 STEP -1
   IF i^2 =< Aa(1) THEN
      LET B(1)=i
      EXIT FOR
   END IF
NEXT i
LET Q(1)=(Aa(1)-B(1)^2)*100+Aa(2)
LET W(1)=20*B(1)
FOR i=2 TO INT((z+1)/2)
   FOR j=9 TO 1 STEP -1
      IF (W(i-1)+j)*j =< Q(i-1) THEN
         LET B(i)=j
         EXIT FOR
      END IF
   NEXT j
   LET Q(i)=(Q(i-1)-(W(i-1)+B(i))*B(i))*100+Aa(i+1)
   IF Q(i)=0 THEN EXIT FOR
   LET W(i)=(W(i-1)+2*B(i))*10
NEXT i
LET S=0
FOR i=1 TO INT((z+1)/2)
   LET S=S+B(i)*10^(INT((z+1)/2)-i)
NEXT i
PRINT "     ";x;"の正の平方根は";S;"です。"
PRINT
END