Why does adding 1.0/3.0 numeric literal three times evaluates to exactly 1 in Golang?

Question

The StackOverflow answer here is very complex for a beginner like me.

Executing the following line of code in Golang results into 1

fmt.Println(1.0/3.0 + 1.0/3.0 + 1.0/3.0)

According to my knowledge, 1.0/3.0 results into 0.3333333... which cannot be stored accurately then what causes this result.

I am not acquainted with low things like how a processor or CPU executes a particular instruction. Can anyone give me a simple answer?

https://golang.org/ref/spec#Constant_expressions – JimB Aug 18 '20 at 14:48 — JimB, Aug 18 '20 at 14:48

score 2 · Accepted Answer · answered Aug 19 '20 at 02:11

According to The Go Programming Language Specification, “Constant expressions are always evaluated exactly…” This means the compiler (or other implementation) is required to do full real-number arithmetic to the extent required to evaluate a constant expression. Thus 1.0/3.0 + 1.0/3.0 + 1.0/3.0 is evaluated as ⅓ + ⅓ + ⅓, which is of course 1.

Why does adding 1.0/3.0 numeric literal three times evaluates to exactly 1 in Golang?

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