C language to achieve the method of static linked list
- 2020-04-01 21:37:45
- OfStack
Before I started, I thought that there was no difference between a static list and a dynamic list. On second thought, I found that there was a topic of memory management hidden in the static list.
The word "static" in a static linked list refers to the source of memory as static memory (usually a global array). Unlike dynamic linked list, in a static linked list nodes in memory the application for and release of all need to maintain, because here is the list, it is easy to think of will spare node link form a free_list, each time need from free_list head a node, is released to the node to the head, so that it can very easy to the realization of the list of other operations.
//Static linked list implementation
#include <stdio.h>
#define MAXN 16 // capacity of list.
typedef int element; // element type.
// define boolean type:
typedef int bool;
#define true -1
#define false 0
#define NPTR -1 // null pointer definition. can not between 0 to MAXN-1.
typedef int pointer;
#define DEBUGVAL(x) printf("%s: %dn", #x, (x)); // a macro for debug.
struct __node
{
element data;
pointer next;
}SLList[MAXN];
pointer ifree, idata;
#define nextof(p) SLList[p].next
#define dataof(p) SLList[p].data
#define _alloc(d) ifree; dataof(ifree)=(d); ifree != NPTR ? ifree=nextof(ifree) : NPTR
#define _free(p) nextof(p)=ifree; ifree = p
void init()
{
int i;
ifree = 0;
idata = NPTR;
for( i=0; i < MAXN-1; i++)
nextof(i) = i+1;
nextof(i) = NPTR;
}
// clear all nodes.
void clear() { init(); }
// push val to front.
bool push_front(element val)
{
pointer tmp, np;
if( ifree != NPTR ) {
np = _alloc(val);
nextof(np) = idata;
idata = np;
return true;
}
return false;
}
// push val to end of list.
bool push_back(element val)
{
if( idata == NPTR ) { //Empty table, write directly
idata = _alloc(val);
nextof(idata) = NPTR;
return true;
}
if( ifree != NPTR ) { //Not empty, find the last node first
pointer last = idata, np;
while( nextof(last) != NPTR ) last = nextof(last);
np = _alloc(val);
nextof(np) = NPTR;
nextof(last) = np;
return true;
}
return false;
}
// insert val to after p pointed node.
bool insert_after(pointer p, element val)
{
if( ifree != NPTR && p != NPTR ) {
pointer pn = _alloc(val);
nextof(pn) = nextof(p);
nextof(p) = pn;
return true;
}
return false;
}
// insert to the position in front of p.
bool insert(pointer ptr, element val)
{
if( ifree == NPTR ) return false; //No nodes, just return
if( ptr == idata ) { //There is a node
pointer np = _alloc(val);
nextof(np) = idata;
idata = np;
return true;
}
else { //In other cases, find the precursor of PTR and insert it
pointer p = idata;
while( p != NPTR ) {
if( nextof(p) == ptr ) { // find p -- the prev node of ptr.
return insert_after(p, val); // insert val after p.
}
p = nextof(p);
}
}
return false;
}
// find element, return the prev node pointer.
pointer find_prev(element val)
{
pointer p = idata;
while( p != NPTR ) {
if( dataof( nextof(p) ) == val )
return p;
p = nextof(p);
}
return NPTR;
}
// find element, return the node pointer.
pointer find(element val)
{
pointer p = idata;
while( p != NPTR ) {
if( dataof(p) == val ) return p;
p = nextof(p);
}
return NPTR;
}
// pop front element.
void pop_front()
{
if( idata != NPTR ) { //Move the first node of the data list to the free list
#if 0
pointer p = idata;
idata = nextof(idata); // idata = nextof(idata);
nextof(p) = ifree; // SLList[p].next = ifree;
ifree = p;
#else
pointer p = idata;
idata = nextof(idata);
_free(p);
#endif
}
}
// pop back element.
void pop_back()
{
if( idata == NPTR ) return;
if( nextof(idata) == NPTR ) { // only 1 node.
nextof(idata) = ifree;
ifree = idata;
idata = NPTR;
}
else { //Find the last node, p, and its precursor, q.
// TODO: find the last node p, and it's perv node q.
pointer p = idata, q;
while( nextof(p) != NPTR ) {
q = p;
p = nextof( p );
}
// remove *p to free list, update nextof(q) to NPTR.
nextof(p) = ifree;
ifree = p;
nextof(q) = NPTR;
}
}
void show()
{
pointer p = idata;
for( ; p != NPTR; p = nextof(p) ) {
printf(" %3d ", dataof(p) );
}
printf("n");
}
#define INFOSHOW
void info()
{
#ifdef INFOSHOW
int i;
DEBUGVAL(ifree);
DEBUGVAL(idata);
puts("====================n"
"indextdatatnextn"
"--------------------");
for(i=0; i<MAXN; i++) {
printf("%dt%dt%dn", i, SLList[i].data, SLList[i].next);
}
puts("====================n");
#endif
}
int main()
{
int i;
init();
#if 1 // push_front test:
puts("push_front test:");
for(i=0; i<MAXN+2; i++) {
push_front(2*i+1);
show();
}
puts("pop_front test:");
for(i=0; i<MAXN+2; i++) {
pop_front();
show();
}
#endif
#if 1 // push_back test:
puts("push_back test:");
for(i=0; i<MAXN+2; i++) {
push_back((i+1)*10);
show();
}
puts("pop_back test:");
for(i=0; i<MAXN+1; i++)
{
pop_back();
show();
}
#endif
#if 1 // insert test:
puts("insert test:");
for(i=0; i<MAXN+2; i++)
{
insert(idata, (i+1)*10);
show();
}
puts("clear...n");
clear();
#endif
#if 1 // insert_after test:
puts("insert_after test:");
push_back(-99);
for(i=0; i<MAXN+1; i++) {
insert_after(idata, i+1);
show();
}
puts("clear...n");
clear();
#endif
#if 1 // find test:
puts("find test:");
for(i=0; i<MAXN/2; i++) {
push_front(MAXN-i);
push_back(MAXN/2-i);
//show();
}
show();
info();
for(i=0; i<MAXN; i++) {
int val = rand()%(2*MAXN);
pointer p = find(val);
if( p != NPTR )
printf("%3d %3d found at %dn", val, dataof(p), p);
else
printf("%3d not foundn", val);
}
#endif
#if 1
puts("nfind_prev test:");
for(i=0; i<MAXN; i++) {
int val = rand()%(2*MAXN);
pointer p = find_prev(val);
if( p != NPTR )
printf("%3d %3d found at %d's next.n", val, dataof(nextof(p)), p);
else
printf("%3d not foundn", val);
}
#endif
#if 1 // find_prev and insert_after test:
clear();
puts("nfind_prev and insert_after test:");
for(i=0; i<MAXN/2; i++) {
push_front(MAXN/2-i);
}
show();
for(i=0; i<MAXN/2; i++) {
int val = rand()%(2*MAXN), n=-(i+1);
pointer p = find_prev(val);
if( p != NPTR ) {
printf("insert %d to front of %d:", n, val);
insert_after(p, n);
show();
}
}
#endif
#if 1 // find and insert test:
clear();
puts("nfind and insert test:");
for(i=0; i<MAXN/2; i++) {
push_front(MAXN/2-i);
}
show();
for(i=0; i<MAXN/2; i++) {
int val = rand()%MAXN, n=-(i+1);
pointer p = find(val);
if( p != NPTR ) {
printf("insert %d to after of %d:", n, val);
insert_after(p, n);
show();
}
}
#endif
puts("end of main().");
return 0;
}
//
The test results are as follows:
push_front test:
1
3 1
5 3 1
7 5 3 1
9 7 5 3 1
11 9 7 5 3 1
13 11 9 7 5 3 1
15 13 11 9 7 5 3 1
17 15 13 11 9 7 5 3 1
19 17 15 13 11 9 7 5 3 1
21 19 17 15 13 11 9 7 5 3 1
23 21 19 17 15 13 11 9 7 5 3 1
25 23 21 19 17 15 13 11 9 7 5 3 1
27 25 23 21 19 17 15 13 11 9 7 5 3 1
29 27 25 23 21 19 17 15 13 11 9 7 5 3 1
29 27 25 23 21 19 17 15 13 11 9 7 5 3 1
29 27 25 23 21 19 17 15 13 11 9 7 5 3 1
pop_front test:
27 25 23 21 19 17 15 13 11 9 7 5 3 1
25 23 21 19 17 15 13 11 9 7 5 3 1
23 21 19 17 15 13 11 9 7 5 3 1
21 19 17 15 13 11 9 7 5 3 1
19 17 15 13 11 9 7 5 3 1
17 15 13 11 9 7 5 3 1
15 13 11 9 7 5 3 1
13 11 9 7 5 3 1
11 9 7 5 3 1
9 7 5 3 1
7 5 3 1
5 3 1
3 1
1
push_back test:
20
20 30
20 30 40
20 30 40 50
20 30 40 50 60
20 30 40 50 60 70
20 30 40 50 60 70 80
20 30 40 50 60 70 80 90
20 30 40 50 60 70 80 90 100
20 30 40 50 60 70 80 90 100 110
20 30 40 50 60 70 80 90 100 110 120
20 30 40 50 60 70 80 90 100 110 120 130
20 30 40 50 60 70 80 90 100 110 120 130 140
20 30 40 50 60 70 80 90 100 110 120 130 140 150
20 30 40 50 60 70 80 90 100 110 120 130 140 150 160
20 30 40 50 60 70 80 90 100 110 120 130 140 150 160
20 30 40 50 60 70 80 90 100 110 120 130 140 150 160
pop_back test:
20 30 40 50 60 70 80 90 100 110 120 130 140 150
20 30 40 50 60 70 80 90 100 110 120 130 140
20 30 40 50 60 70 80 90 100 110 120 130
20 30 40 50 60 70 80 90 100 110 120
20 30 40 50 60 70 80 90 100 110
20 30 40 50 60 70 80 90 100
20 30 40 50 60 70 80 90
20 30 40 50 60 70 80
20 30 40 50 60 70
20 30 40 50 60
20 30 40 50
20 30 40
20 30
20
insert test:
10
20 10
30 20 10
40 30 20 10
50 40 30 20 10
60 50 40 30 20 10
70 60 50 40 30 20 10
80 70 60 50 40 30 20 10
90 80 70 60 50 40 30 20 10
100 90 80 70 60 50 40 30 20 10
110 100 90 80 70 60 50 40 30 20 10
120 110 100 90 80 70 60 50 40 30 20 10
130 120 110 100 90 80 70 60 50 40 30 20 10
140 130 120 110 100 90 80 70 60 50 40 30 20 10
150 140 130 120 110 100 90 80 70 60 50 40 30 20 10
150 140 130 120 110 100 90 80 70 60 50 40 30 20 10
150 140 130 120 110 100 90 80 70 60 50 40 30 20 10
clear...
insert_after test:
-99 1
-99 2 1
-99 3 2 1
-99 4 3 2 1
-99 5 4 3 2 1
-99 6 5 4 3 2 1
-99 7 6 5 4 3 2 1
-99 8 7 6 5 4 3 2 1
-99 9 8 7 6 5 4 3 2 1
-99 10 9 8 7 6 5 4 3 2 1
-99 11 10 9 8 7 6 5 4 3 2 1
-99 12 11 10 9 8 7 6 5 4 3 2 1
-99 13 12 11 10 9 8 7 6 5 4 3 2 1
-99 14 13 12 11 10 9 8 7 6 5 4 3 2 1
-99 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
-99 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
-99 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
clear...
find test:
10 11 12 13 14 15 16 8 7 6 5 4 3 2 1
ifree: -1
idata: 14
====================
index data next
--------------------
16 1
8 3
15 0
7 5
14 2
6 7
13 4
5 9
12 6
4 11
11 8
3 13
10 10
2 15
9 12
1 -1
====================
9 found at 14
3 found at 11
not found
4 found at 9
1 found at 15
12 found at 8
not found
14 found at 4
not found
16 found at 0
9 found at 14
not found
not found
not found
9 found at 14
11 found at 10
find_prev test:
not found
6 found at 3's next.
not found
not found
7 found at 1's next.
12 found at 10's next.
not found
not found
4 found at 7's next.
not found
13 found at 8's next.
not found
6 found at 3's next.
not found
7 found at 1's next.
not found
find_prev and insert_after test:
2 3 4 5 6 7 8
insert -4 to front of 8: 1 2 3 4 5 6 7 -4 8
insert -5 to front of 3: 1 2 -5 3 4 5 6 7 -4 8
insert -8 to front of 6: 1 2 -5 3 4 5 -8 6 7 -4 8
find and insert test:
2 3 4 5 6 7 8
insert -2 to after of 3: 1 2 3 -2 4 5 6 7 8
insert -6 to after of 8: 1 2 3 -2 4 5 6 7 8 -6
insert -7 to after of 5: 1 2 3 -2 4 5 -7 6 7 8 -6
end of main().