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Guest
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| Weird atof() conversion |
 Posted: Tue Feb 21, 2006 4:57 am |
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Hi all,
i have some problem converting string to long and unable to figure it out. My program receives reads about 21 characters on the RS-232 and selects all the digits in it, stores it in another array and then convert it into long. If the digits are ABC in variable 'digitsrx' then after conversion prints 0BC. Can u suggest a possible solution, why this doesnt convert this SIMPLE string.
Following is the code:
| Code: |
#include <16f877a.h>
#device *=16
#include<stdlib.h>
//#include<input.c>
#fuses XT,NOWDT,NOLVP,NOPROTECT,BROWNOUT //--> try these also
#use delay (clock=4000000,restart_wdt)
#use rs232(baud=4800,xmit=PIN_C6,rcv=PIN_C7,stream=DEV,ERRORS)
#include<lcd.c>
long feet=0;
long feeta=0;
char digitsrx[4]={0};
int i=0,j=0;
char rxdata[21]={0};
char endptr[4];
void main()
{
lcd_init();
lcd_gotoxy(1,1);
while(1)
{
fgets(rxdata,DEV);
j=0;
for(i=0;i<21;i++)
{
if(isdigit(rxdata[i]))
{
digitsrx[j]=rxdata[i];
j++;
}
}
digitsrx[j]='\0'; // terminating with NULL
for(i=0; i<21;i++)
rxdata[i]=0;
lcd_gotoxy(1,1);
printf(lcd_putc,"%s",digitsrx); // correct result printed
feet=strtod(digitsrx,endptr); // converted ascii to long
lcd_gotoxy(1,2);
printf(lcd_putc,"%lu",feet); // wrong result
feeta=atol(digitsrx);
lcd_gotoxy(10,2);
printf(lcd_putc,"%lu",feeta); //wrong result
}
}
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rwyoung
Joined: 12 Nov 2003
Posts: 563
Location: Lawrence, KS USA
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| Posted: Tue Feb 21, 2006 9:01 am |
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So if your first loop finds more than 3 digits, what happens? Your array | Code: | | char digitsrx[4]={0}; |
will fall apart!
This may not be the ultimate problem but you definately will have an issue later.
By the way, what is your compiler version number? There is a history of funny behavior with some of the built-in functions.
_________________
Rob Young
The Screw-Up Fairy may just visit you but he has crashed on my couch for the last month! |
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KenMacfarlane
Joined: 20 Sep 2005
Posts: 23
Location: Glasgow, Scotland, UK
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| Me too! |
| Posted: Tue Mar 07, 2006 4:38 am |
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I'm having similar problems with pcwh v3.235 on an 18f6621 (yes, I know that its not the latest, but the latest contains a bug that I'm waiting for CCS to fix):
| Code: |
sprintf(pszTmp, "1234567"); // crashes too: Resets to start of main
fPart2 = strtod(pszTmp, &remptr);
dwPart2 = (int32)fPart2
// strtod also crashes with 8 digit null term'd str 34628712
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Incidentally, is there code for a 32 bit version of strtoul around? That's what I really want - the above code, including strtod, could be replaced by such a function. |
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