Rounding numbers (both ways)
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Im in a C++ MFC visual studio 6.0 workspace. i have a float, which i need to round, both mathematically and string wise.. For example mathematically this; 0.306-> 0.31 0.99-> 1.00 and string wise; 0.12000000 -> 0.12 12.0000000 -> 12 Ive surfed around, but only found ones that dont remove unnecessary zeros, and dont work perfectly for all numbers.. The variable i have is a float, and im guessing its atof thats creating the extra zeros (which i have to use, or something equivalent) rounding should be to 2dp, ie allways x.xx any ideas? thanks!
/Johannes
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Im in a C++ MFC visual studio 6.0 workspace. i have a float, which i need to round, both mathematically and string wise.. For example mathematically this; 0.306-> 0.31 0.99-> 1.00 and string wise; 0.12000000 -> 0.12 12.0000000 -> 12 Ive surfed around, but only found ones that dont remove unnecessary zeros, and dont work perfectly for all numbers.. The variable i have is a float, and im guessing its atof thats creating the extra zeros (which i have to use, or something equivalent) rounding should be to 2dp, ie allways x.xx any ideas? thanks!
/Johannes
Johpoke wrote:
For example mathematically this; 0.306-> 0.31 0.99-> 1.00
This is int integer = (int)(0.306 + 0.5);
Johpoke wrote:
and string wise; 0.12000000 -> 0.12 12.0000000 -> 12
Maybe boosts format library[^] can help you?
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Im in a C++ MFC visual studio 6.0 workspace. i have a float, which i need to round, both mathematically and string wise.. For example mathematically this; 0.306-> 0.31 0.99-> 1.00 and string wise; 0.12000000 -> 0.12 12.0000000 -> 12 Ive surfed around, but only found ones that dont remove unnecessary zeros, and dont work perfectly for all numbers.. The variable i have is a float, and im guessing its atof thats creating the extra zeros (which i have to use, or something equivalent) rounding should be to 2dp, ie allways x.xx any ideas? thanks!
/Johannes
Johpoke wrote:
0.306-> 0.31 0.99-> 1.00
this is a matter of representation, so basically, printf() does it ! for the 2 questions btw, you can have a look here[^]
[VisualCalc][Flags Beginner's Guide] | [Forums Guidelines][My Best Advice]
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Im in a C++ MFC visual studio 6.0 workspace. i have a float, which i need to round, both mathematically and string wise.. For example mathematically this; 0.306-> 0.31 0.99-> 1.00 and string wise; 0.12000000 -> 0.12 12.0000000 -> 12 Ive surfed around, but only found ones that dont remove unnecessary zeros, and dont work perfectly for all numbers.. The variable i have is a float, and im guessing its atof thats creating the extra zeros (which i have to use, or something equivalent) rounding should be to 2dp, ie allways x.xx any ideas? thanks!
/Johannes
There's also the
ceil()andfloor()functions. It's really just a matter of trying each suggestion until you find the one that does just what you need.
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Im in a C++ MFC visual studio 6.0 workspace. i have a float, which i need to round, both mathematically and string wise.. For example mathematically this; 0.306-> 0.31 0.99-> 1.00 and string wise; 0.12000000 -> 0.12 12.0000000 -> 12 Ive surfed around, but only found ones that dont remove unnecessary zeros, and dont work perfectly for all numbers.. The variable i have is a float, and im guessing its atof thats creating the extra zeros (which i have to use, or something equivalent) rounding should be to 2dp, ie allways x.xx any ideas? thanks!
/Johannes
Strings:
CString str; float f = 0.306; //float f = 12.0000000f; str.Format(_T("%.2g"), f); TRACE(_T("%s\n"), str);Because I've used %g (instead of %f), 12.0 will be 12. Numerics: Take a look at this: http://www.codeproject.com/cpp/floatutils.asp[^]
- Dy
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Strings:
CString str; float f = 0.306; //float f = 12.0000000f; str.Format(_T("%.2g"), f); TRACE(_T("%s\n"), str);Because I've used %g (instead of %f), 12.0 will be 12. Numerics: Take a look at this: http://www.codeproject.com/cpp/floatutils.asp[^]
- Dy
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Now, that seems good, but it does lots of weird things that i dont want, try setting f to, 299.99 or 31.2699 thanks!!
/Johannes
that's normal floating point behavior... know that their height storage capability is at the cost of the precision
[VisualCalc][Flags Beginner's Guide] | [Forums Guidelines][My Best Advice]
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that's normal floating point behavior... know that their height storage capability is at the cost of the precision
[VisualCalc][Flags Beginner's Guide] | [Forums Guidelines][My Best Advice]
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Im in a C++ MFC visual studio 6.0 workspace. i have a float, which i need to round, both mathematically and string wise.. For example mathematically this; 0.306-> 0.31 0.99-> 1.00 and string wise; 0.12000000 -> 0.12 12.0000000 -> 12 Ive surfed around, but only found ones that dont remove unnecessary zeros, and dont work perfectly for all numbers.. The variable i have is a float, and im guessing its atof thats creating the extra zeros (which i have to use, or something equivalent) rounding should be to 2dp, ie allways x.xx any ideas? thanks!
/Johannes
Well, that's not very "generic" (what happens when you need to round at a higher precision?).
double Rounder(double fVal, int nPrecision)
{
nPrecision = __max(__min(16, nPrecision), 1);
double fEpsilon = pow(10, nPrecision);
double fResult = ( floor(fVal * fEpsilon + 0.5) / fEpsilon);
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