#include<\/span> <\/span><stdio.h><\/span>
<\/span>#include<\/span> <\/span><stdlib.h><\/span>
<\/span>typedef<\/span> <\/span>struct<\/span> <\/span>l1<\/span> <\/span>{<\/span>
<\/span>struct<\/span> <\/span>l1<\/span>*<\/span> <\/span>next<\/span>;<\/span>
<\/span>int<\/span> <\/span>key<\/span>;<\/span>
<\/span>}<\/span> <\/span>l1<\/span>;<\/span>
<\/span>l1<\/span>*<\/span> <\/span>head<\/span> <\/span>=<\/span> <\/span>NULL<\/span>;<\/span>
<\/span>l1<\/span>*<\/span> <\/span>insert_head<\/span>(<\/span>int<\/span> <\/span>key<\/span>)<\/span> <\/span>{<\/span>
<\/span>l1<\/span>*<\/span> <\/span>p<\/span>;<\/span>
<\/span>p<\/span> <\/span>=<\/span> <\/span>(<\/span>l1<\/span>*)<\/span> <\/span>malloc<\/span>(<\/span>sizeof<\/span>(<\/span>struct<\/span> <\/span>l1<\/span>));<\/span>
<\/span>if<\/span>(<\/span>p<\/span> <\/span>==<\/span> <\/span>NULL<\/span>)<\/span> <\/span>{<\/span>
<\/span>printf<\/span>(<\/span>"<\/span>No memory<\/span>\\n<\/span>"<\/span><\/span>);<\/span>
<\/span>return<\/span> <\/span>NULL<\/span>;<\/span>
<\/span>}<\/span>
<\/span>p<\/span>-><\/span>key<\/span> <\/span>=<\/span> <\/span>key<\/span>;<\/span>
<\/span>p<\/span>-><\/span>next<\/span> <\/span>=<\/span> <\/span>head<\/span>;<\/span>
<\/span>head<\/span> <\/span>=<\/span> <\/span>p<\/span>;<\/span>
<\/span>return<\/span> <\/span>p<\/span>;<\/span>
<\/span>}<\/span>
<\/span>l1<\/span>*<\/span> <\/span>insert_tail<\/span>(<\/span>int<\/span> <\/span>key<\/span>)<\/span> <\/span>{<\/span>
<\/span>l1<\/span>**<\/span> <\/span>tail<\/span>;<\/span>
<\/span>l1<\/span>*<\/span> <\/span>p<\/span>;<\/span>
<\/span>tail<\/span> <\/span>=<\/span> <\/span>&<\/span>head<\/span>;<\/span>
<\/span>p<\/span> <\/span>=<\/span> <\/span>(<\/span>l1<\/span>*)<\/span> <\/span>malloc<\/span>(<\/span>sizeof<\/span>(<\/span>struct<\/span> <\/span>l1<\/span>));<\/span>
<\/span>if<\/span>(<\/span>p<\/span> <\/span>==<\/span> <\/span>NULL<\/span>)<\/span> <\/span>{<\/span>
<\/span>printf<\/span>(<\/span>"<\/span>No memory<\/span>\\n<\/span>"<\/span><\/span>);<\/span>
<\/span>return<\/span> <\/span>NULL<\/span>;<\/span>
<\/span>}<\/span>
<\/span>p<\/span>-><\/span>key<\/span> <\/span>=<\/span> <\/span>key<\/span>;<\/span>
<\/span>p<\/span>-><\/span>next<\/span> <\/span>=<\/span> <\/span>NULL<\/span>;<\/span> |