Providing feedback when processing a large for loop

[Mark Waes]

Hi,

This should be easy, but for the life of me I can't figure it out...

I'm looking to provide user feeback when processing a large for-loop, and at each 10% milestone, print the message '10% Complete', '20% Complete' etc..

my code is below, but it suffers from a problem when the countTarget instance variable is an odd number (prime numbers being a specific example) in that not all of the 10% milestones are printed.

Regardless of the number of interations required by the for-loop, I would like to print feedback 10 times.

for (int i = 0; i <= this.countTarget; i++) {
   double a = (double) i;
   double b = (double) this.countTarget;
   double mileStone = a / b * 100;
   if (mileStone % 10 == 0.0) {
      System.out.println(i + " of " + this.countTarget + ", which is " + (int) (mileStone) + "% complete");
   }
}

Any help gratefully received...

[fred rosenberger]

the problem is you're using floats here, and floating point arithmetic is never precise. What i'd probably do is something like

//prior to your loop
int benchmark = this.countTarget / 10;  // note: integer division here


//inside your loop
if (i == benchmark)
   {
    //print message
    benchmark += this.countTarget / 10;
   } 

You may not get your output at EXACTLY 10%, but pretty dang close.