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VanHauser
Joined: 03 Oct 2005
Posts: 88
Location: Ploiesti, Romania
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| printf() odd behavior with floats |
 Posted: Fri May 19, 2006 4:39 am |
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I'm using PCH 3.249. The printf() function does not seem to format %f fields correctly. This is my test code, on 18F252:
| Code: | printf("%f\r\n", 0.0001);
printf("%f\r\n", 12.0);
printf("%f\r\n", 9999.0);
printf("%f\r\n", -13.25);
printf("%f\r\n", 13.45);
printf("%f\r\n", -1999.0);
printf("%f\r\n", -0.000035);
printf("%f\r\n", -9999.0); |
And this is what I get:
| Code: | 0.000100
12.000000
1409.065987
-13.250000
13.450000
-1999.000064
-0.000035
-1409.065987 |
9999.0 and -9999.0 are not displayed correctly  Some advice, anyone? |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Fri May 19, 2006 11:50 am |
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This is a known bug with the "%f" format specifier. To fix it, you need
to put in the width and precision fields. Also, the width field must be
greater than the precision field.
It's best if you always put in the width and precision fields.
Don't use the plain "%f" specifier.
| Quote: |
#include <16F877.H>
#fuses XT, NOWDT, NOPROTECT, BROWNOUT, PUT, NOLVP
#use delay(clock=4000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, ERRORS)
//============================
void main()
{
printf("%f\r\n", 0.0001);
printf("%f\r\n", 12.0);
printf("%7.5f\r\n", 9999.0);
printf("%f\r\n", -13.25);
printf("%f\r\n", 13.45);
printf("%f\r\n", -1999.0);
printf("%f\r\n", -0.000035);
printf("%7.5f\r\n", -9999.0);
while(1);
} |
References:
http://www.ccsinfo.com/forum/viewtopic.php?t=26059&start=6
http://www.ccsinfo.com/forum/viewtopic.php?t=24719&start=1 |
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