Cursor implementation

CURSOR IMPLEMENTATION

 Cursor implementation is nothing but the linked list representation using
array.

 Operations:

• Initialization of array

• Insertion: Insert new element at postion pointed by header(ZERO)
and assign new position which is null to header.

•Deletion: Delete an element and assign that position to header(ZERO)

•Traversal: Display the entire array


#include <iostream.h>
#include <conio.h>

#define SIZE 11

struct node
{
char element;
int nextpos;
};
typedef struct node cursor;

cursor cursorspace[SIZE];

void intialize()
{
for(int i=0;i<SIZE-1;i++)
{ cursorspace[i].element = 'x';
cursorspace[i].nextpos = i+1;
}
cursorspace[SIZE-1].element = 'x';
cursorspace[SIZE-1].nextpos = 0;
}
void display()
{
cout<<"nCursor Implementation ";
cout<<"n------------------------------------";
cout<<"n"<<setw(6)<<"Slot"<<setw(12)<<"Element"<<setw(16)
<<"Next Position";
for(int i=0;i<SIZE;i++)
{ cout<<endl<<setw(4)<<i<<" ";
cout<<cursorspace[i].element;
cout<<setw(15)<<cursorspace[i].nextpos;
cout<<endl;
}
}


Cursor Implementation
------------------------------------
Slot Element Next Position
0 x 1
1 x 2
2 x 3
3 x 4
4 x 5
5 x 6
6 x 7
7 x 8
8 x 9
9 x 10
10 x 0

void insert(char x) Cursor Implementation
{ ------------------------------------
int tmp; Slot Element Next Position
0 x 2
tmp = cursoralloc(); 1 A 2
2 x 3
if(tmp==0) 3 x 4
cout<<"nError-Outof space."; 4 x 5
else 5 x 6
cursorspace[tmp].element = x; 6 x 7
7 x 8
} 8 x 9
int cursoralloc() 9 x 10
{ 10 x 0
int p;
p = cursorspace[0].nextpos;
cursorspace[0].nextpos = cursorspace[p].nextpos;
return p;
}


Cursor Implementation Cursor Implementation Cursor Implementation
---------------------------------- ---------------------------------- ----------------------------------
Slot Element Next Slot Element Next Slot Element Next

Position Position Position
0 x 2 0 x 3 0 x 6
1 A 2 1 A 2 1 A 2
2
3
x
x
3
4
 2
3
B
x
3
4
 2 B 3
3 C 4
4 x 5 4 x 5 4 D 5
5 x 6 5 x 6 5 E 6
6 x 7 6 x 7 6 x 7
7 x 8 7 x 8 7 x 8
8 x 9 8 x 9 8 x 9
9 x 10 9 x 10 9 x 10
10 x 0 10 x 0 10 x 0

void del(char x)
{
int p,tmp;

p = findprevious(x);

if(p==0)
{
tmp=1;
cursorfree(tmp);
}
else
{
tmp = cursorspace[p].nextpos;
cursorspace[p].nextpos = cursorspace[tmp].nextpos;
cursorfree(tmp);
}
}

int findprevious(char x)
{
int p=0;
if(cursorspace[1].element==x)
{
return 0;
}

for(int i=0;x!=cursorspace[i].element;i++)
{
p = cursorspace[i].nextpos;
}//gives index of element to be deleted

for(i=0;cursorspace[i].nextpos!=p;i++);

p=i;//gives index of previous element
return p;
}


void cursorfree(int p)
{
for(int i=cursorspace[p].nextpos;i<SIZE-1;i++)
{
if(cursorspace[i].nextpos==cursorspace[0].nextpos)
{
cursorspace[i].nextpos=p;
break;
}
}
cursorspace[p].nextpos = cursorspace[0].nextpos;
cursorspace[p].element = 'x';
cursorspace[0].nextpos = p;

}


Cursor Implementation Cursor Implementation
------------------------------------ ------------------------------------
Slot Element Next Position Slot Element Next Position
0 x 6 0 x 4
1 A 2 1 A 2
2 B 3 2 B 3
3 C 4
Delete D
3 C 5
4 D 5  4 x 6
5 E 6 5 E 4
6 x 7 6 x 7
7 x 8 7 x 8
8 x 9 8 x 9
9 x 10 9 x 10
10 x 0 10 x 0


Cursor Implementation Cursor Implementation
------------------------------------ ------------------------------------
Slot Element Next Position Slot Element Next Position
0 x 4 0 x 3
1 A 2 1 A 2
2 B 3 2 B 5
3 C 5
Delete C
3 x 4
4 x 6  4 x 6
5 E 4 5 E 3
6 x 7 6 x 7
7 x 8 7 x 8
8 x 9 8 x 9
9 x 10 9 x 10
10 x 0 10 x 0

Cursor implementation

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