Pascal Lazaruz doesn't do its division properly for some instances

Asked Apr 28 '20 at 17:20

Active Apr 28 '20 at 18:09

Viewed 123 times

program Project1;

var p : real;

const s=439 ;

begin
     p:=s/100;
     Write(p);
     ReadLn;
end.

Output of the above code is expected to be 4.39, but this gives 4.3899999999999997E+000. Where do these additional 89999999 came from? How to omit this and get the correct answer? Thanks in advance!

P.S. If we assign s = 433 it gives the expected output as 4.3300000000000001E+000. My issue is, how this division can be number related?

Edit: I want to know a remedy to overcome this inaccuracy. It may be a code line or two, what ever possible to get rid of this issue.

edited Apr 28 '20 at 18:09

asked Apr 28 '20 at 17:20

Dovini Jayasinghe

1

It's a question of how e.g. real-type numbers are represented as a limited number of bits. – MartynA Apr 28 '20 at 17:36
@500-InternalServerError Thank you so much for the link provided. It solves my issue half-way, but I need to know whether there's any remedy to fix this. – Dovini Jayasinghe Apr 28 '20 at 18:06
2

There's no way to eliminate rounding errors like this, but you can round the result to the desired precision when outputting it with e.g. `Write(p:7:2);`. – 500 - Internal Server Error Apr 28 '20 at 18:09
@500-InternalServerError Could you kindly explain your example? I'm a beginner to Pascal. – Dovini Jayasinghe Apr 28 '20 at 18:11
1

Here, `p:7:2` instruct `Write` to display the value of variable `p` in a 7-character field, with 2 decimal places. – 500 - Internal Server Error Apr 28 '20 at 18:13
Thanks a lot. Let me give a try. – Dovini Jayasinghe Apr 28 '20 at 18:16
You can do this arithmetic the way you want. You just been to use a decimal type rather than a binary type. – David Heffernan Apr 28 '20 at 22:38

Pascal Lazaruz doesn't do its division properly for some instances

0 Answers0