float to ascii conversion

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momar128

Joined: 09 Sep 2003
Posts: 5
Location: Pakistan

24 Sep 2003 11:12 float to ascii

I need to convert floating point number into ASCII Character in C language.
Can anyone illustrate me with simple example.

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artem

Joined: 22 May 2003
Posts: 1652
Helped: 91
Location: Turan

24 Sep 2003 16:37 float to ascii conversion in c

- get the format those are stored (your C compiler documentation must tell that )in your memory
- get bytes from memory according to format above
and convert them byte by byte to the ascii acccording
to byte meaning .

C-Man

Joined: 19 Jul 2001
Posts: 1235
Helped: 73

24 Sep 2003 17:28 float to ascii in c

This is highly machine dependant, you should be able to what you need if your compiler has the sprintf library function which acts like printf but puts the result into a buffer (memory) from where you can extract the ascii representation of your float.

I also included a routine I found on the net, but as said before this is machine dependant!!!

If possible use sprintf.

hope this helps

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nebisman

Joined: 13 Apr 2002
Posts: 291
Helped: 1

24 Sep 2003 20:40 ieee754 ascii conversion

If you use the IEEE 754 (most usual) norm for float remember:

bit 31 sign
bit 23-30 exponent with excess to 127 (0 es 127)
bit 0 -22 mantissa

then you can eloborate a function which is composed union mixed with estructure for return these fields and then traduce then to ASCII. This union return the fields in BYTES for trasmision over a RS232 channel.

Code:

union {
double num_float;
long int num_longint;
int num_int;
struct dividir{
char byte3;
char byte2;
char byte1;
char byte0;
}bytes;
}number;

and access to fields for this example:

void
tx_float (double num_tx){
numero.num_float = num_tx;
putch(numero.bytes.byte3);
putch(numero.bytes.byte2);
putch(numero.bytes.byte1);
putch(numero.bytes.byte0);
}

then only set the fields for return the sign, exponent,mantissa, if I understand your problem, and with simple function convert it to ASCII code ex. -1.25 e 24. (sign ,mantissa ,exponen)

amir81

Joined: 01 Mar 2003
Posts: 44
Helped: 5

24 Sep 2003 20:45 float to ascii conversion

you can use thses functions:

AnsiString __fastcall FloatToStr(Extended Value);

AnsiString __fastcall FloatToStrF(Extended Value, TFloatFormat Format, int Precision, int Digits);

int __fastcall FloatToText(char * Buffer, const void *Value, TFloatValue ValueType, TFloatFormat Format, int Precision, int Digits);

int __fastcall FloatToTextFmt(char * Buffer, const void *Value, TFloatValue ValueType, char * Format);