Why Does Go Compiler Error Out on Division by Zero with Floats?

Go Compiler Error: Float Zero Division

In Go, attempting to divide a finite float by zero results in a compilation error. This behavior may seem counterintuitive, especially considering that dividing two finite floating-point numbers usually results in an infinity, as depicted in the following example:

<code class="go">func main() {
  var y float64 = 0.0
  var x float64 = 4.0 / y
  fmt.Println(x)
}</code>

Output:

+Inf

However, dividing a finite float by zero triggers a compiler error:

<code class="go">func main() {
  var x float64 = 4.0 / 0.0
  fmt.Println(x)
}</code>

Output:

prog.go:9:22: division by zero

Reason for the Compiler Error

This behavior stems from the unique representation of numeric constants in Go. Unlike most programming languages that directly map numerical constants to IEEE754 float types, Go treats numeric constants as exact values of arbitrary precision. Consequently, Go cannot inherently store infinity or negative zero.

This design choice provides benefits in terms of avoiding overflows in constant calculations, as demonstrated by the following example:

<code class="go">var x float64 = 1e1000 / 1e999 // yes, this is 10</code>

Alternative for Representing Infinity

If you specifically require an infinity value, you can use the math.Inf(1) function to represent positive infinity or math.Inf(-1) for negative infinity.

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