@@ -93,6 +93,62 @@ static void drlink_insert(drlink_data **drldata, unsigned int loc, char data)
9393 ndrldata -> prev = temp ;
9494}
9595
96+ static void drlink_delete (drlink_data * * drldata , unsigned int loc )
97+ {
98+ int i = 0 ;
99+ drlink_data * drlp = * drldata ;
100+ drlink_data * temp ;
101+ if (!drlp ) {
102+ printf ("drlink is not exsit\n" );
103+ return ;
104+ }
105+
106+ if (drlp -> next == * drldata && loc == 0 ) { // head 0 0
107+ free (drlp );
108+ * drldata = NULL ;
109+ return ;
110+ }
111+ if (loc == 0 ) { //head 0... 1 1
112+ temp = drlp -> prev ;
113+ temp -> next = drlp -> next ;
114+ drlp -> next -> prev = temp ;
115+ free (* drldata );
116+ * drldata = temp -> next ;
117+ return ;
118+ }
119+ for (; i < loc ; i ++ ) { // head... n
120+ if (drlp -> next == * drldata ) {
121+ printf ("delete loc %d is invalid\n" , loc );
122+ return ;
123+ }
124+ drlp = drlp -> next ;
125+ }
126+ temp = drlp -> prev ;
127+ temp -> next = drlp -> next ;
128+ drlp -> next -> prev = temp ;
129+ free (drlp );
130+ drlp = NULL ;
131+ }
132+
133+ static void drlink_amend (drlink_data * drldata , unsigned int loc , char data )
134+ {
135+ int i = 0 ;
136+ drlink_data * drlp = drldata ;
137+ if (!drlp ) {
138+ printf ("drlink is not exsit\n" );
139+ return ;
140+ }
141+
142+ for (; i < loc ; i ++ ) {
143+ drlp = drlp -> next ;
144+ if (drlp == drldata ) {
145+ printf ("amend loc %d is invalid\n" , loc );
146+ return ;
147+ }
148+ }
149+ drlp -> data = data ;
150+ }
151+
96152int main ()
97153{
98154 drlink_data * drldata ;
@@ -109,9 +165,25 @@ int main()
109165 drlink_show (drldata );
110166 drlink_insert (& drldata , 4 , 'i' );
111167 drlink_show (drldata );
168+ drlink_insert (& drldata , 2 , 'm' );
169+ drlink_show (drldata );
170+
171+ drlink_delete (& drldata , 0 );
172+ drlink_show (drldata );
173+ drlink_delete (& drldata , 1 );
174+ drlink_show (drldata );
175+ drlink_delete (& drldata , 2 );
176+ drlink_show (drldata );
177+ drlink_delete (& drldata , 2 );
178+ drlink_show (drldata );
179+
180+ drlink_amend (drldata , 1 , 'p' );
181+ drlink_show (drldata );
182+ drlink_amend (drldata , 0 , 'u' );
183+ drlink_show (drldata );
184+ drlink_amend (drldata , 2 , 'y' );
185+ drlink_show (drldata );
112186#if 0
113- drlink_delete ();
114- drlink_amend ();
115187 drlink_select ();
116188 drlink_destroy ();
117189#endif
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