On 13 July 2011 02:30, eric wrote: > it can compile but when I run it > ----------- > eric@eric-laptop:~/cppcookbook/ch7$ ./a.out > Enter a series of strings: a z b y c x d w^Z > [1]+ Stopped ./a.out > ---------------------------------- > it sould suppose to show > ----- > a b c d w x y z Only on Windows. ^Z on Linux is not the same as Windows. If the book says it should show that then THE BOOK IS WRONG. As I said, use a different book, or use a different compiler + operating system. The book you're using only works on Windows. Also, stop asking these questions here. Thanks.