Hi all,
Can someone explain why the following error happens:
#define bla "\xA"
char a [2] = {0};
memcpy (a,bla,1); // a[0] = 0x0a <- Correct
//a[1] = bla; // '=' : cannot convert from 'const char [2]' to 'char'
Thanks,
RM
views:
130answers:
2
+5
A:
The types are different: a[1] is a char and "\xA" is an array of char.
In C++ and C anything enclosed in double quotes (including nothing) is an array of char.
anon
2009-07-22 19:30:09
Yes but should char[1] assigned to char work ?and why is it a char [2] array ?
Roman M
2009-07-22 19:32:04
You're declaring a string which implicitly has a terminating zero character (U+0000) at the end, so "x" is two characters: x and \0
Joey
2009-07-22 19:32:49
I thought \xA is treated as single byte i.e bla should be a single byte (char) array ? I thought \xA is treated a single byte i.e bla should be a single byte (char) array ? – Roman M 0 secs ago [delete this comment]
Roman M
2009-07-22 19:35:57
Don't forget that all strings are terminated with \0, so even if you assign a single char in the string its still two.
Shay Erlichmen
2009-07-22 19:39:36
\xA is a single byte, but since you put it in double quotes and not single quotes, it is treated as a string (not a character) and so has an implicit nul byte after it to terminate the string.
Tyler McHenry
2009-07-22 19:40:30
This answers the question correctly.
EvilTeach
2010-05-09 14:27:49
+4
A:
Try:
#define bla '\xA'
Although that will stop the memcpy working.
Daniel Earwicker
2009-07-22 19:38:25
Bingo.So if I use " " it treats it creates a null terminated array of charand if I user ' ' it just treats it like a char right ?
Roman M
2009-07-22 19:42:04