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float to CString conversion not exact

17
For a reason i don't know, if i convert a float to a cstring, it does not convert to an exact value for all values except round numbers or 1/2 numbers;

the following code (used to convert and later show as text in a MFC Document)
Expand|Select|Wrap|Line Numbers
  1. char buffer1[_CVTBUFSIZE];
  2. _gcvt(i_A11, 12, buffer1);
  3. CString SA11 = (CString) buffer1;
  4.  
output
float i_A11 = 1,2 and once converted to Cstring SA11 = "1.20000004768"
float i_A11 = 1,0 and once converted to Cstring SA11 = "1."
float i_A11 = 1,5 and once converted to Cstring SA11 = "1.5"

thanks in advance for the help!
Feb 12 '08 #1
1 4711
JosAH
11,448 Expert 8TB
Read What every computer scientist should know about floating-point arithmetic.

kind regards,

Jos
Feb 12 '08 #2

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