convert decimal to ascii

Projects Programming
1

Hi,

I am on a Yun, so I use FileIO class.

When I open a file which is located on the SD card, using FileSystem.open(), I read decimal and not ASCII characters. >:(
How can I read / convert ASCII values ?

Thanks

2

Can you post your code? I imagine you can do this:

// get file
File myfile = FileSystem.open("myfile.txt");

//Check if this didn't work
if (!myfile) {
   print("This is broken");
   exit;
}

// read a byte
char my_char = myfile.read();
3

file.read() is defined to return an int. If you use a numeric datatype variable to read into, you'll get an integer ascii code. If you use a char datatype, it will convert it from ascii to a character for you.

File thefile = FileSystem.open( "thefile.txt");
if( thefile )
{ int  d_char = thefile.read();   // <-- d_char will be a integer ascii code.
  byte b_char = thefile.read();   // <-- b_char will be a integer ascii code.
  long l_char = thefile.read();   // <-- l_char will be a integer ascii code.
  char c_char = thefile.read();   // <-- c_char will be a character.
}

Also you should be able to convert between the two using these:

char AsciiToChar( byte asciiCode )   { return (asciiCode +'\0' ); }
byte CharToAscii( char character )   { return (character -'\0' ); }
4

Or you can use a simple cast:

File thefile = FileSystem.open( "thefile.txt");
if( thefile )
{ int  d_char = thefile.read();   // <-- d_char will be a integer ascii code.
  byte b_char = thefile.read();   // <-- b_char will be a integer ascii code.
  long l_char = thefile.read();   // <-- l_char will be a integer ascii code.
  char c_char = thefile.read();   // <-- c_char will be a character.

// Every type here can be cast and printed as a char:

Serial.println( (char) d);
Serial.println( (char) b);
Serial.println( (char) l);
Serial.println(  c);
}
5

yup.