c# - Why is infinity printed as "8" in the Windows 10 console?

Question

I was testing what was returned from division including zeroes i.e. 0/1, 1/0 and 0/0. For this I used something similar to the following:

Console.WriteLine(1d / 0d);

However this code prints 8 not Infinity or some other string constant like PositiveInfinity.

For completeness all of the following print 8:

Console.WriteLine(1d / 0d);

double value = 1d / 0d;
Console.WriteLine(value);

Console.WriteLine(Double.PositiveInfinity);

And Console.WriteLine(Double.NegativeInfinity); prints -8.

Why does this infinity print 8?

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For those of you who seem to think this is an infinity symbol not an eight the following program:

Console.WriteLine(1d / 0d);

double value = 1d / 0d;
Console.WriteLine(value);

Console.WriteLine(Double.PositiveInfinity);

Console.WriteLine(8);

Outputs:

Answer 1

Be assured that the floating point value is +Infinity if the numerator of a floating point division by zero is positive, -Infinity if the numerator of a floating point division by zero is negative, and NaN if the numerator and denominator of a floating point division are both zero. That's in the IEEE754 floating point specification, which is what C# uses.

In your case, the console is converting the infinity symbol (which is sometimes represented typographically as a horizontal 8 — ∞) to a vertical 8.