Decimal Places

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Views: 363 | Replies: 6 | Solved

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Join Date: Dec 2007

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Decimal Places

Jul 17th, 2008

I am trying to get quite a large number 0.00012354684 to X required decimal places.

Using <iomanip> and setprecision() but I cant seem to get it to work.

Could someone please give me a small example.

Thankyou, Regards X

"You never stop learning" - OmniX

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Join Date: Oct 2007

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Re: Decimal Places

Jul 18th, 2008

How large is X? What is the type of your large number? 0.00012354584 is actually quite small

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Re: Decimal Places

Jul 18th, 2008

number = 0.00012354684
type = float
decimal points vary = 1-5

"You never stop learning" - OmniX

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Re: Decimal Places

Jul 18th, 2008

Use double (~16 decimal digits); 32-bit floats keep only ~5-7 decimal digits.
Always use double type in math calculations!

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Re: Decimal Places

Jul 18th, 2008

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Originally Posted by OmniX

Using <iomanip> and setprecision() but I cant seem to get it to work.

Could someone please give me a small example.

ok:

 Help with Code Tags 
 cpp Syntax (Toggle Plain Text) 
    float a = 0.00012354684; 
    //number has 8 meaningfull digits (skip the first zero's)
    cout <<  setprecision (8) << a << "\n";
    cout <<  setprecision (5) << a << "\n";
    cout <<  setprecision (3) << a << "\n";
    cout <<  setprecision (1) << a << "\n";
    float a = 0.00012354684; 
    //number has 8 meaningfull digits (skip the first zero's)
    cout <<  setprecision (8) << a << "\n";
    cout <<  setprecision (5) << a << "\n";
    cout <<  setprecision (3) << a << "\n";
    cout <<  setprecision (1) << a << "\n";

output:

Help with Code Tags

(Toggle Plain Text)

0.00012354684
0.00012355
0.000124
0.0001

What doesn't work in your program? Post your code.

Last edited by niek_e : Jul 18th, 2008 at 5:27 am.

Want better/more replies to your questions? Wrap your code in [code] [/code] tags!
do NOT pm me for help, in the best case, you'll get ignored

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Re: Decimal Places

Jul 18th, 2008

Nice work niek_e again!

I found my problem:
- is there something I should be aware of when dividing 2 numbers in C++?
- thats why I am getting no decimal points?

Another small example, please?

Thankyou, Regards X

"You never stop learning" - OmniX

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Re: Decimal Places

Jul 18th, 2008

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Originally Posted by OmniX

- is there something I should be aware of when dividing 2 numbers in C++?
- thats why I am getting no decimal points?

try this:

 Help with Code Tags 
 cpp Syntax (Toggle Plain Text) 
    float a = 1.2, b = 0.5;
    int c = 2, d = 3;
    cout << "two floats: " << a/b << "\n"; 
    cout << "two ints: " << d/c << "\n"; 
    cout << "float and int: " << a/c << "\n"; 
    float a = 1.2, b = 0.5;
    int c = 2, d = 3;
    cout << "two floats: " << a/b << "\n"; 
    cout << "two ints: " << d/c << "\n"; 
    cout << "float and int: " << a/c << "\n"; 