Doubles are giving me problems


Posted on 16th Feb 2014 07:03 pm by admin

Ok so, first of all i made a double = 0.05, but when running the debugger it shows up as 0.04999. I know this has something to do with how doubles store but its causing problems for me. Anyway, in the code I'm trying to get only the right hand side(rhs) of the double variable jdn's decimal point. So in the code example I'm only trying to get .05. But rhs isn't always going to be the same and can have up to 0.00005 <- that fifth one there(can't remember what its called - hundred thousandth?). I have constant numbers right now for the sake of testing this. Now the counter goes through starting at 0.1, to make sure everything after the decimal point is 0. It goes through fine until it gets to 0.0002 - 0.0001 and then rhs = 9.99998e-005.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
#include #include #include using namespace std; int main() { double jdn = 2454115.05; double lhs = floor(jdn); double rhs = jdn - lhs; double counter = 0.1; if( rhs != 0.0 ) while( (rhs != 0.000001) || (counter != 0.00001) ) { if( (rhs - counter) <= 0 ) { counter *= 0.1; //cout << "rhs = " << rhs << endl; } else { rhs -= counter; cout << "rhs = " << rhs << endl; } } cout << "ok" << endl; return 0; }
Results:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
rhs = 0.04 rhs = 0.03 rhs = 0.02 rhs = 0.01 rhs = 0.009 rhs = 0.008 rhs = 0.007 rhs = 0.006 rhs = 0.005 rhs = 0.004 rhs = 0.003 rhs = 0.002 rhs = 0.001 rhs = 0.0009 rhs = 0.0008 rhs = 0.0007 rhs = 0.0006 rhs = 0.0005 rhs = 0.0004 rhs = 0.0003 rhs = 0.0002 rhs = 9.99998e-005

No comments posted yet

Your Answer:

Login to answer
120 Like 6 Dislike
Previous forums Next forums
Other forums

question about stripslashes and real_escape_string
im cleaning up an old app that I wrote fixing some of the vulernabilities from attacks.

I hav

present value of sequence?
Hi

Please help me to find out the present value of sequence?

Thanks

Taylor Series Function
So I am working a a project for my intro C++ class, and I am having some trouble with a function for

Why does this file not return file names that start with numbers?
This file returns a list of filenames to help populate a drop down in my form. For some reason it ig

Good Programming and Web Design Books
Hi,

I recived a pm today from a fellow phpfreaker regarding php books, i replied with the fo

Preserving user-entered linebreaks
Hi, I'm building a web 2.0 thingy from scratch and I wanna display text which users input. It's all

How to get the previous months last date....
Here's my wittle problem. I suck at working with dates.

So today is 10/20/2009, i need to fig

$_FILES array
Ok,

I just started experimenting with PHP today. My goal right now is to have people be able

Auto-populating dropdowns and multiple forms.
Here's what I have so far:

First drop down = select a state (works)
This populates the sec

reorder sql query
ok so i have this very simple code:
Code: $query = "SELECT search_keywords, COUNT(search_key

Sign up to write
Sign up now if you have flare of writing..
Login   |   Register
Follow Us
Indyaspeak @ Facebook Indyaspeak @ Twitter Indyaspeak @ Pinterest RSS



 
© indyaspeak.com. All Rights Reserved.
Play Free Quiz and Win Cash