Math question (or how to resolve this)

[Pvt-Colli]

Hi all,

If i use this simple code:

10 CLS
20 TIME = 2.4
30 LOCATE 10,10:PRINT TIME
40 A$=INKEY$
50 IF A$= CHR$(32) THEN TIME = TIME + .9
60 GOTO 30

The printed results are:
2.4
3.3
4.200001

Why does the 4.2 has the extra 00001 behind it? And how can i resolve this so it is exactly 4.2?

[robhagemans]

This is because floating-point representation cannot precisely represent every decimal fraction. You're using single-precision here; you could get smaller error by using double precision floats (TIME#). Alternatively, multiply all your numbers by 10 and use integer math.

[Pvt-Colli]

This is because floating-point representation cannot precisely represent every decimal fraction. You're using single-precision here; you could get smaller error by using double precision floats (TIME#). Alternatively, multiply all your numbers by 10 and use integer math.

I added this line:
55 TIME = CINT (TIME * 10) / 10

This does the job, only after 60 or so steps it goes wrong. But i only need 6 :-)