Why Does Go Print Negative Integers as \'-ff\' While C Prints \'fffffffffffffff\' When Using \'%x\'?

Printing Negative Hexadecimal Integers in Go vs. C

When printing an integer value of -1 using the "%x" format specifier, Go and C behave differently. In Go, the output is "-1," while in C, it is "fffffffffffffff," as expected.

Go's Behavior

Go considers the "%x" format specifier to represent the value of the number in hexadecimal notation, regardless of whether it is negative. Thus, for -1, the hexadecimal value is "-ff."

C's Behavior

In contrast, C prints memory representations of integers using the "%x" specifier. Since -1 is typically stored in 2's complement form, its hexadecimal representation in memory is "fffffffffffffff."

Unifying Behavior with Type Conversions

To achieve C-like behavior in Go, one must explicitly convert the signed integer to its unsigned equivalent before applying the "%x" format specifier. For instance:

i := -1 // type int
fmt.Printf("%x", uint(i)) // prints "fffffffffffffff"

Rationale for Go's Default

Rob Pike, a Go developer, explains the reasoning behind Go's default behavior:

"Why is that not the default [the unsigned format]? Because if it were, there would be no way to print something as a negative number, which as you can see is a much shorter representation."

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