Sending floating point numbers to serial stream- aht2printfloat

My thanks to "mem" at the Arduino forum for the following code, and for permission to post it here. He did say it was put together quickly, so do please get in touch (with me) if you discover any "features" which need attention!

Serial.print does not print floating point. Here is a sketch with a function you can use to display a "double" type value, giving whatever number of decimal places you need. The function is followed by a simple "setup" and "loop" exercising the function.

Remember: You don't need extra hardware to see what is being produced by Serial.println.... just click on the Serial Monitor icon on the Arduino development environment's toolbar. I have a How To explaining that, if you are interested.

/*Program to provide and demonstrate a way
  to send floating point numbers to the serial
  stream.*/

double x;
double y;
double z;

void printDouble( double val, unsigned int precision){
/* prints val with number of decimal places determine by precision
   NOTE: precision is 1 followed by the number of zeros for the
   desired number of decimal places
   Example:
   printDouble( 3.1415, 100); // prints 3.14 (two decimal places)
   */

    Serial.print (int(val));  //prints the int part
    Serial.print("."); // print the decimal point
    unsigned int frac;
    if(val >= 0)
	  frac = (val - int(val)) * precision;
    else
	  frac = (int(val)- val ) * precision;
    Serial.println(frac,DEC) ;
}

void  setup(){
  Serial.begin(9600);
  Serial.println("Print floating point example");
  printDouble( 3.1415, 100);
       /* Previous line is an example of call to
          printDouble to print pi to two decimal places*/
  x = 10;
  y = 3.1;
  z = x / y;
  delay(3000);// Give reader a chance to see the output.
}


 void loop(){
   printDouble(z,10);   // one decimal place
   printDouble(z,100);  // two decimal places
   printDouble(z,1000); // three decimal places
   z = z + .1;
   delay(100);
 }

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"Printing" floating point numbers over the serial stream