diff --git a/related_info/lab0/lab0_ex3.c b/related_info/lab0/lab0_ex3.c
index b59c7ee..4d2ce7e 100644
--- a/related_info/lab0/lab0_ex3.c
+++ b/related_info/lab0/lab0_ex3.c
@@ -49,3 +49,68 @@ main(void)
     
     return 0;
 }
+
+// other examples
+//ex1
+#if 0
+#include <stdlib.h>
+#include <stdio.h>
+#include <iostream>
+#include <cstring>
+
+#define STS_TG32 0xF
+#define STS_IG32 0xE
+#define SETGATE( gate, istrap, sel, off, dpl) {            \
+    (gate).gd_off_15_0 = (uint32_t)(off) & 0xffff;        \
+    (gate).gd_ss = (sel);                                \
+    (gate).gd_args = 0;                                    \
+    (gate).gd_rsv1 = 0;                                    \
+    (gate).gd_type = (istrap) ? STS_TG32 : STS_IG32;    \
+    (gate).gd_s = 0;                                    \
+    (gate).gd_dpl = (dpl);                                \
+    (gate).gd_p = 1;                                    \
+    (gate).gd_off_31_16 = (uint32_t)(off) >> 16;        \
+}
+using namespace std;
+
+
+struct gatedesc {
+    unsigned gd_off_15_0 : 16;        // low 16 bits of offset in segment
+    unsigned gd_ss : 16;            // segment selector
+    unsigned gd_args : 5;            // # args, 0 for interrupt/trap gates
+    unsigned gd_rsv1 : 3;            // reserved(should be zero I guess)
+    unsigned gd_type : 4;            // type(STS_{TG,IG32,TG32})
+    unsigned gd_s : 1;                // must be 0 (system)
+    unsigned gd_dpl : 2;            // descriptor(meaning new) privilege level
+    unsigned gd_p : 1;                // Present
+    unsigned gd_off_31_16 : 16;        // high bits of offset in segment
+};
+
+
+
+
+
+int main()
+{   
+    gatedesc intr;
+
+    intr.gd_off_15_0 = 8;
+    intr.gd_ss = 0;
+    intr.gd_args = 0;
+    intr.gd_rsv1 = 0;
+    intr.gd_type = 0;
+    intr.gd_s = 0;
+    intr.gd_dpl = 0;
+    intr.gd_p = 0;
+    intr.gd_off_31_16 = 0;
+
+    SETGATE( intr, 0,1,2,3);
+
+    printf( "%u\n",  intr);
+    printf( "%x", intr);
+
+
+
+    return 0;
+}
+#endif
diff --git a/related_info/lab0/lab0_ex4.c b/related_info/lab0/lab0_ex4.c
index 99d8509..6909260 100644
--- a/related_info/lab0/lab0_ex4.c
+++ b/related_info/lab0/lab0_ex4.c
@@ -25,3 +25,146 @@ int main() {
         printf("%d\n", ((struct entry *)p)->num);
     return 0;
 }
+
+// other examples
+
+// ex1
+#if 0
+include "list.h";
+
+void main() { 
+	node_t node1; 
+	node1.data = 1; 
+	list_entry_t *n1 = &nodes1.node_link; 
+	node_t node2; 
+	node2.data = 2; 
+	list_init(n1); 
+	list_add_after(n1, &nodes2.node_link); 
+    printf("\n"); 
+}
+#endif
+
+//ex2
+#if 0
+#include "list.h"
+#include "defs.h"
+#include <stdio.h>
+
+struct page {
+    int test;
+    list_entry_t page_link;
+};
+
+#define le2page(le, member)  to_struct((le), struct page, member)
+
+#define to_struct(ptr, type, member)                               \
+((type *)((char *)(ptr) - offsetof(type, member)))
+
+#define offsetof(type, member)                                      \
+        ((size_t)(&((type *)0)->member))
+
+
+typedef struct {
+    list_entry_t free_list;
+    unsigned int nr_free;
+}free_area_t;
+
+int main(){
+             
+    free_area_t free_area;
+    struct page pg;
+    free_area.free_list.next = &pg.page_link;
+        
+    pg.test = 1;
+    pg.page_link.next = &free_area.free_list;
+    list_entry_t* le = &free_area.free_list;
+    while ( (le = list_next(le)) != &free_area.free_list ) {
+        struct page* p = le2page(le, page_link);
+        printf ( "%d\n", p->test );
+    }
+    return 0;
+}
+#endif
+
+//ex3
+#if 0
+#include <stdio.h>
+#include "list.h"
+
+
+int main(int argc, const char * argv[])
+{
+    list_entry_t HS0,HS1,HS2,HS3;
+
+    list_init(&HS0);
+    printf("%d %d %d\n",HS0.prev, HS0.next, &HS0);
+
+    HS0.prev = NULL;
+    HS0.next = &HS1;
+    HS1.prev = &HS0;
+    HS1.next = &HS2;
+    HS2.prev = &HS1;
+    HS2.next = NULL;
+
+    list_add(&HS1, &HS3);
+
+    printf("%d %d %d\n",HS0.prev, HS0.next, &HS0);
+    printf("%d %d %d\n",HS1.prev, HS1.next, &HS1);
+    printf("%d %d %d\n",HS3.prev, HS3.next, &HS3);
+    printf("%d %d %d\n",HS2.prev, HS2.next, &HS2);
+
+
+    list_del(&HS3);
+    printf("%d %d %d\n",HS0.prev, HS0.next, &HS0);
+    printf("%d %d %d\n",HS1.prev, HS1.next, &HS1);
+    printf("%d %d %d\n",HS2.prev, HS2.next, &HS2);
+}
+#endif
+
+//ex4
+#if 0
+//一个简单的随机生成一个长度的链表并计算长度的程序
+#include <iostream>
+#include <cstdlib>
+#include <cstdio>
+#include <ctime>
+#include "list.h"
+
+using namespace std;
+
+void randlength( list_entry_t *&elm )
+{
+    list_init(elm);
+    int countt = rand()%100;
+
+    printf("the length of the list that will be created: %d\n", countt );
+
+    for( int i = 0; i < countt; i++  )
+    {
+        list_entry_t * node = new list_entry_t();
+        list_add_after(elm, node);
+    }
+}
+
+int getlength( list_entry_t *&elm )
+{
+    int countt = 0;
+    list_entry_t * current_node = elm;
+    while( current_node->next!=elm )
+    {
+        countt ++;
+        current_node = current_node->next;
+    }
+    return countt;
+}
+
+int main()
+{
+    srand( (unsigned)time(NULL));
+    list_entry_t * root = new list_entry_t();
+    randlength( root );
+    printf(" the length of this list is %d", getlength(root) );
+
+    return 0;
+}
+#endif