Weird behavior

Question

So when I run this code, it doesn't exactly behave as I expected it to. Why?
https://code.sololearn.com/cV4Qaucjz2de/?ref=app

Answer 1

Floating point calculation can't be too precious in binary, try to format it to correct decimal point.

Eg. {0:0.000}

https://code.sololearn.com/c14zh0v8XKCk/?ref=app

Answer 2

I observed that Calviղ's code is not the final solution. The last value should stop at 1, but it actually stops at 0.999.

Here are a couple of variations that will fix the for loop as well as the output.

Use this:

for(double i=0.0, j=0.0; i<=1.0; i=0.001*(++j)) {

Or this:

for(double i=0.0; i<=1.0; i=Math.Round(i+0.001,3)) {

Note also that float would suffice for this range of numbers. Using double precision is unnecessary.

Answer 3

This formating is for number only

Answer 4

Daniel Cooper The formatting converts double to a string in fact.

Answer 5

Daniel Cooper for creating a string variable, s:
String s = String.Format("{0:0.000}", i);
https://code.sololearn.com/cqBTSM4Vwv8Y/?ref=app

Answer 6

Calviղ Thanks. I was trying to convert a string to a string. No wonder it wasn't working xD

Answer 7

Daniel Cooper As it's been established, the output is due to the conversion from floating point to binary where precision is limited due to fixed number of bits allotted for a given data type.

You can see these differences when comparing this same code using float and decimal types in the code link below:

https://code.sololearn.com/cXaqUFq4moAx/

You can learn more about accuracy problems with Floating Point Arithmetic in this link:

https://en.m.wikipedia.org/wiki/Floating-point_arithmetic#Accuracy_problems

Answer 8

Calviղ Wait, can I format a string like this?

Answer 9

Calviղ Sorry, just to be clear, I mean convert a double to a string and format it like this. Is that possible?