Using "%s" with inputting numberic values

[Adam D Ruppe]

On Sunday, 24 July 2022 at 23:12:46 UTC, pascal111 wrote:
> In the next code, we used "%s" format with receiving an integer 
> value, while from C experience, we know that we use "%d" or 
> "%i" formats, so what "%s" stands for here, I guess it's for 
> receiving string data type?

The D things in std.stdio, writef and readf, use %s to just mean 
default for the given type. Since you passed it an int, the 
function knows it got an int (this is different than C, where the 
function only knows the format string so it requires you to get 
it right) and just automatically picks a default representation 
to scan.

You can writef("%s %s", "foo", 5); and it will see "foo" is a 
string and thus do it as a regular %s then see 5 is an int and 
since it knows, and you asked for just the default as-string 
representation, it will convert just like %d would.