Why does Go print -1 as \'-1\' in hex format while C prints \'ffffffffffffffff\'?

Hexadecimal Printing Discrepancy Between Go and C

In the Go programming language, printing a 64-bit integer -1 using the %x format results in "-1". However, in C language, the same format would output "ffffffffffffffff" for a positive integer. This behavior may seem counterintuitive at first, but it stems from the fundamental difference in how Go and C handle integer representation.

In Go, the %x verb for integers represents the value of the number using the hexadecimal representation. For negative numbers like -1, its hexadecimal representation is "-ff". This adheres to the Go convention of always explicitly formatting based on type. To print a signed integer as an unsigned value, it must be explicitly converted.

For instance:

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

This behavior ensures consistent representation across different types.

The reasoning behind this default behavior for negative numbers was explained by Rob Pike:

"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."

This means that Go prioritizes brevity and clarity in its formatting conventions. While it may be unexpected to encounter signed hexadecimal numbers, it aligns with Go's emphasis on explicitness and type safety.

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