convert string to a number

[Jim Rogers]

I have an instrument with a serial output. The output string is   X=+03.22 CR LF Y=-04.22 CR LF.  I need to extract the two numbers.

I have been trying to use strtod in the stdlib. Is there an example code showing how to make and use character strings?

[Wolfgang]

Hi,

you might consider scanf instead. Refer to userint\standardio.cws for an example of using the scanf function.

[ebalci · Accepted solution]

If this is the only thing your instrument sends out, X and Y values one after the other, then you can do this:

char buffer[16];

double valX, valY;

ComRdTerm (port, buffer, 15, 13); // 13 = CR byte value

valX = atof (&buffer[2]);

ComRdTerm (port, buffer, 15, 13);

valY = atof (&buffer[2]);

[Jim Rogers]

Thanks for the help. Atof fixed the prob

Jim R

[ebalci]

I need to correct my code a little. In order to atof work correctly it must see a null character to understand where the string ends.

Here is the corrected version.

char buffer[16];

int len;

double valX, valY;

len = ComRdTerm (port, buffer, 15, 13); // 13 = CR byte value

buffer[len] = 0;

valX = atof (&buffer[2]);

ComRdTerm (port, buffer, 15, 13);

buffer[len] = 0;

valY = atof (&buffer[2]);

[Wolfgang]

Sorry... but I would suggest one more (minor) change

char buffer[16];

int len;

double valX, valY;

len = ComRdTerm (port, buffer, 15, 13); // 13 = CR byte value

buffer[len] = 0;

valX = atof (&buffer[2]);

len = ComRdTerm (port, buffer, 15, 13);

buffer[len] = 0;

valY = atof (&buffer[2]);

[ebalci]

Thank you Wolfgang, I had forgotten to put it there...

Now we have a complete code!... 😉