nwtnsqrt.bas

[ARRL.无线电通讯手册].The.Arrl.Handbook.For.Radio.Communications.-.2007

DEFDBL A
DEFINT D, G, K-M                       '
DEFLNG N-T                             '
DERROR = 1                             'COMPUTE TO WITHIN 1 BIT
                                       '
START: PRINT : INPUT "ARGUMENT"; ARG   'THE ARGUMENT
 IF ARG <> INT(ARG) THEN GOTO START    'MUST BE INTEGRAL
 PARG = ARG                            'ARGUMENT IS A 32-BIT #
 N = (LOG(PARG)) / (LOG(2))            '# OF SIG FIGS IN PARG
 OLDGUESS = 2 ^ (N / 2)                'GOOD INITIAL GUESS
                                       '
LOOP0: FOR K = 0 TO 8191               '''''''''ITERATION COUNTER
 NEWGUESS = (PARG / OLDGUESS + OLDGUESS) / 2   'THE NEW GUESS
IF ABS(NEWGUESS-OLDGUESS)<=DERROR THEN K0 = K: K = 8191: GOTO FIN
 OLDGUESS = NEWGUESS                           'NEW IS NOW OLD
                                               '
FIN: NEXT K                                    'GO MORE

 PRINT "SQR("; PARG; ")="; NEWGUESS; ", ITERATIONS="; K0 + 1
 GOTO START