Incrementing 0.1 in floating point number 0.0 gives unexpected result in Dart

Question

I was writing a code to print the sequence 0.1, 0.2, 0.3, ......,1.0 in Dart. I used while loop and wrote the following code

void main() {
  var i = 0.0;
  while (i <= 1) {
    print(i);
    i += 0.1;
  }
}

now the compiler is giving me an unexpected result of my code

0.1
0.2
0.30000000000000004
0.4
0.5
0.6
0.7
0.7999999999999999
0.8999999999999999
0.9999999999999999

Can anyone tell what exactly is happening

Relevant: [What Every Computer Scientist Should Know About Floating-Point Arithmetic](https://docs.oracle.com/cd/E19957-01/806-3568/ncg_goldberg.html) — lepsch, Sep 14 '22 at 09:44
Suppose you changed your increment step to `i += 1./3;`. Since 1/3 = 0.333333 is an infinitely-repeating decimal fraction, you would not be surprised if you saw a few anomalies like this. Well, it turns out that, in the binary systems that computers typically use, 1/10 is an infinitely-repeating fraction, too. In decimal it's 0.1 exactly, but in binary it's `0.00011001100110011…` . — Steve Summit, Sep 14 '22 at 18:08

score -1 · Answer 1 · answered Sep 14 '22 at 09:51

-1

If you need to print this toStringAsPrecision can fix this If you need it to be double again try double.parse(i.toStringAsPrecision(2));

void main() {
  var i = 0.0;
  while (i <= 1) {
    print(i.toStringAsPrecision(2));
    i += 0.1;
  }
}

answered Sep 14 '22 at 09:51

Aakash Ghimire

1 Answers1