printfのなかで\xを使ってみなさいという演習。
[ERROR:13]% cat 1-2.c [/home/utadaq/work/kandr]
#include <stdio.h>
main(){
printf("hello, world\x",0x0c);
}
[5418]% gcc 1-2.c -o 1-2 [/home/utadaq/work/kandr]
1-2.c:4:9: \x used with no following hex digits
[ERROR:1]% [/home/utadaq/work/kandr]