We have discussed
and insert operations. In this post,
delete operation
is discussed. When we want to delete a character these three cases may arise.
-
Characters to be deleted is at cursor position: Let’s assume we want to delete “FOR” from “FORGEEKS”, since the cursor (gap_left) is at desired position the character is deleted i.e. the gap takes the character inside itself and the character gets deleted.
-
Characters to be deleted is left of cursor position: For this case since “FOR” is left to the cursor position we must reach to the desired position by using left() as in previous article. Now, we can delete “FOR” as in case 1.
-
Characters to be deleted is right of cursor position: For this case also the cursor position is right to the desired position we must reach there by using right() as in previous article. Now, we can delete “FOR” as in case 1.
Implementing Gap Buffer with Deletion
CPP
// C++ program of implementation// of gap buffer with Deletion#include <bits/stdc++.h>using namespace std;
char buffer[50];
int gap_size = 10;
int gap_left = 0;
int gap_right = gap_size - gap_left - 1;
int size = 10;
// Function that is used to grow the gap// at index position and return the arrayvoid grow(int k, int position)
{ char a[size];
// Copy characters of buffer to a[]
// after position
for (int i = position; i < size; i++) {
a[i - position] = buffer[i];
}
// Insert a gap of k from index position
// gap is being represented by '-'
for (int i = 0; i < k; i++) {
buffer[i + position] = '_';
}
// Reinsert the remaining array
for (int i = 0; i < position + k; i++) {
buffer[position + k + i] = a[i];
}
size += k;
gap_right += k;
}// Function that is used to move the gap// left in the arrayvoid left(int position)
{ // Move the gap left character by character
// and the buffers
while (position < gap_left) {
gap_left--;
gap_right--;
buffer[gap_right + 1] = buffer[gap_left];
buffer[gap_left] = '_';
}
}// Function that is used to move the gap// right in the arrayvoid right(int position)
{ // Move the gap right character by character
// and the buffers
while (position > gap_left) {
gap_left++;
gap_right++;
buffer[gap_left - 1] = buffer[gap_right];
buffer[gap_right] = '_';
}
}// Function to control the movement of gap// by checking its position to the point of// insertionvoid move_cursor(int position)
{ if (position < gap_left) {
left(position);
}
else {
right(position);
}
}// Function to insert the string to the buffer// at point positionvoid insert(string input, int position)
{ int len = input.length();
int i = 0;
// If the point is not the gap check
// and move the cursor to that point
if (position != gap_left) {
move_cursor(position);
}
// Insert characters one by one
while (i < len) {
// If the gap is empty grow the size
if (gap_right == gap_left) {
int k = 10;
grow(k, position);
}
// Insert the character in the gap and
// move the gap
buffer[gap_left] = input[i];
gap_left++;
i++;
position++;
}
}// Function to delete the character buffer// at point positionvoid deleetion(int position)
{ // If the point is not the gap check
// and move the cursor to that point
if (position + 1 != gap_left) {
move_cursor(position + 1);
}
// Reduce the gap_left
gap_left -= 1;
buffer[gap_left] = '_';
}// Driver codeint main()
{ // Initializing the gap buffer with size 10
for (int i = 0; i < 10; i++) {
buffer[i] = '_';
}
cout << "Initializing the gap buffer "
<< "with size 10" << endl;
for (int i = 0; i < size; i++) {
cout << buffer[i] << " ";
}
cout << endl;
// Inserting a string to buffer
string input = "GEEKSGEEKS";
int position = 0;
insert(input, position);
cout << endl;
cout << "Inserting a string to buffer"
<< ": GEEKSGEEKS" << endl;
cout << "Output: ";
for (int i = 0; i < size; i++) {
cout << buffer[i] << " ";
}
input = "FOR";
position = 5;
// Inserting a string to buffer
insert(input, position);
cout << endl;
cout << endl;
cout << "Inserting a string to buffer"
<< ": FOR" << endl;
cout << "Output: ";
for (int i = 0; i < size; i++) {
cout << buffer[i] << " ";
}
position = 5;
// Deletion a character from buffer
deleetion(position);
cout << endl;
cout << endl;
cout << "Deleting character at position 5"
<< endl;
cout << "Output: ";
for (int i = 0; i < size; i++) {
cout << buffer[i] << " ";
}
position = 6;
// Deletion a character from buffer
deleetion(position);
cout << endl;
cout << endl;
cout << "Deleting character at position 6"
<< endl;
cout << "Output: ";
for (int i = 0; i < size; i++) {
cout << buffer[i] << " ";
}
position = 5;
// Deletion a character from buffer
deleetion(position);
cout << endl;
cout << endl;
cout << "Deleting character at position 5"
<< endl;
cout << "Output: ";
for (int i = 0; i < size; i++) {
cout << buffer[i] << " ";
}
input = "HELLO";
position = 0;
// Inserting a string to buffer
insert(input, position);
cout << endl;
cout << endl;
cout << "Inserting a string to buffer"
<< ": HELLO" << endl;
cout << "Output: ";
for (int i = 0; i < size; i++) {
cout << buffer[i] << " ";
}
return 0;
} |
Java
public class GapBuffer {
// Define the buffer and gap variables
private char[] buffer;
private int gapSize = 10;
private int gapLeft = 0;
private int gapRight = gapSize - 1;
private int size = 10;
// Constructor to initialize the gap buffer
public GapBuffer() {
buffer = new char[50];
for (int i = 0; i < 10; i++) {
buffer[i] = '_';
}
}
// Function to increase the size of the gap
public void grow(int k, int position) {
char[] a = new char[size];
System.arraycopy(buffer, position, a, 0, size - position);
for (int i = 0; i < k; i++) {
buffer[i + position] = '_';
}
System.arraycopy(a, 0, buffer, position + k, size - position);
size += k;
gapRight += k;
}
// Function to move the gap to the left
public void left(int position) {
while (position < gapLeft) {
gapLeft--;
gapRight--;
buffer[gapRight + 1] = buffer[gapLeft];
buffer[gapLeft] = '_';
}
}
// Function to move the gap to the right
public void right(int position) {
while (position > gapLeft) {
gapLeft++;
gapRight++;
buffer[gapLeft - 1] = buffer[gapRight];
buffer[gapRight] = '_';
}
}
// Function to move the cursor to the desired position
public void moveCursor(int position) {
if (position < gapLeft) {
left(position);
} else {
right(position);
}
}
// Function to insert a string at a given position
public void insert(String input, int position) {
int len = input.length();
int i = 0;
if (position != gapLeft) {
moveCursor(position);
}
while (i < len) {
if (gapRight == gapLeft) {
int k = 10;
grow(k, position);
}
buffer[gapLeft] = input.charAt(i);
gapLeft++;
i++;
position++;
}
}
// Function to delete a character at a given position
public void deletion(int position) {
if (position + 1 != gapLeft) {
moveCursor(position + 1);
}
gapLeft -= 1;
buffer[gapLeft] = '_';
}
// Function to print the current state of the buffer
public void printBuffer() {
for (int i = 0; i < size; i++) {
System.out.print(buffer[i] + " ");
}
System.out.println();
}
// Main function to demonstrate the gap buffer operations
public static void main(String[] args) {
GapBuffer gapBuffer = new GapBuffer();
System.out.println("Initializing the gap buffer with size 10");
gapBuffer.printBuffer();
System.out.println("\nInserting a string to buffer: GEEKSGEEKS");
gapBuffer.insert("GEEKSGEEKS", 0);
gapBuffer.printBuffer();
System.out.println("\nInserting a string to buffer: FOR");
gapBuffer.insert("FOR", 5);
gapBuffer.printBuffer();
System.out.println("\nDeleting character at position 5");
gapBuffer.deletion(5);
gapBuffer.printBuffer();
System.out.println("\nDeleting character at position 6");
gapBuffer.deletion(6);
gapBuffer.printBuffer();
System.out.println("\nDeleting character at position 5");
gapBuffer.deletion(5);
gapBuffer.printBuffer();
System.out.println("\nInserting a string to buffer: HELLO");
gapBuffer.insert("HELLO", 0);
gapBuffer.printBuffer();
}
} |
Python3
class GapBuffer:
def __init__(self):
# Initializing the gap buffer
self.buffer = ['_']*50
self.gapSize = 10
self.gapLeft = 0
self.gapRight = self.gapSize - 1
self.size = 10
def grow(self, k, position):
# Increasing the size of the gap
a = self.buffer[position:self.size]
self.buffer[position:position+k] = ['_']*k
self.buffer[position+k:position+k+self.size-position] = a
self.size += k
self.gapRight += k
def left(self, position):
# Moving the gap to the left
while position < self.gapLeft:
self.gapLeft -= 1
self.gapRight -= 1
self.buffer[self.gapRight + 1] = self.buffer[self.gapLeft]
self.buffer[self.gapLeft] = '_'
def right(self, position):
# Moving the gap to the right
while position > self.gapLeft:
self.gapLeft += 1
self.gapRight += 1
self.buffer[self.gapLeft - 1] = self.buffer[self.gapRight]
self.buffer[self.gapRight] = '_'
def moveCursor(self, position):
# Moving the cursor to the desired position
if position < self.gapLeft:
self.left(position)
else:
self.right(position)
def insert(self, input, position):
# Inserting a string at a given position
len_input = len(input)
i = 0
if position != self.gapLeft:
self.moveCursor(position)
while i < len_input:
if self.gapRight == self.gapLeft:
k = 10
self.grow(k, position)
self.buffer[self.gapLeft] = input[i]
self.gapLeft += 1
i += 1
position += 1
def deletion(self, position):
# Deleting a character at a given position
if position + 1 != self.gapLeft:
self.moveCursor(position + 1)
self.gapLeft -= 1
self.buffer[self.gapLeft] = '_'
def printBuffer(self):
# Printing the current state of the buffer
print(' '.join(self.buffer[:self.size]))
if __name__ == "__main__":
gapBuffer = GapBuffer()
print("Initializing the gap buffer with size 10")
gapBuffer.printBuffer()
print("\nInserting a string to buffer: GEEKSGEEKS")
gapBuffer.insert("GEEKSGEEKS", 0)
gapBuffer.printBuffer()
print("\nInserting a string to buffer: FOR")
gapBuffer.insert("FOR", 5)
gapBuffer.printBuffer()
print("\nDeleting character at position 5")
gapBuffer.deletion(5)
gapBuffer.printBuffer()
print("\nDeleting character at position 6")
gapBuffer.deletion(6)
gapBuffer.printBuffer()
print("\nDeleting character at position 5")
gapBuffer.deletion(5)
gapBuffer.printBuffer()
print("\nInserting a string to buffer: HELLO")
gapBuffer.insert("HELLO", 0)
gapBuffer.printBuffer()
|
C#
using System;
using System.Linq;
public class GapBuffer
{ private char[] buffer;
private int gapSize;
private int gapLeft;
private int gapRight;
private int size;
public GapBuffer()
{
// Initializing the gap buffer
this.buffer = Enumerable.Repeat('_', 50).ToArray();
this.gapSize = 10;
this.gapLeft = 0;
this.gapRight = this.gapSize - 1;
this.size = 10;
}
private void Grow(int k, int position)
{
// Increasing the size of the gap
var a = this.buffer.Skip(position).Take(this.size - position).ToArray();
Array.Copy(a, 0, this.buffer, position + k, this.size - position);
Array.Fill(this.buffer, '_', position, k);
this.size += k;
this.gapRight += k;
}
private void Left(int position)
{
// Moving the gap to the left
while (position < this.gapLeft)
{
this.gapLeft--;
this.gapRight--;
this.buffer[this.gapRight + 1] = this.buffer[this.gapLeft];
this.buffer[this.gapLeft] = '_';
}
}
private void Right(int position)
{
// Moving the gap to the right
while (position > this.gapLeft)
{
this.gapLeft++;
this.gapRight++;
this.buffer[this.gapLeft - 1] = this.buffer[this.gapRight];
this.buffer[this.gapRight] = '_';
}
}
public void MoveCursor(int position)
{
// Moving the cursor to the desired position
if (position < this.gapLeft)
{
this.Left(position);
}
else
{
this.Right(position);
}
}
public void Insert(string input, int position)
{
// Inserting a string at a given position
int len_input = input.Length;
int i = 0;
if (position != this.gapLeft)
{
this.MoveCursor(position);
}
while (i < len_input)
{
if (this.gapRight == this.gapLeft)
{
int k = 10;
this.Grow(k, position);
}
this.buffer[this.gapLeft] = input[i];
this.gapLeft++;
i++;
position++;
}
}
public void Deletion(int position)
{
// Deleting a character at a given position
if (position + 1 != this.gapLeft)
{
this.MoveCursor(position + 1);
}
this.gapLeft--;
this.buffer[this.gapLeft] = '_';
}
public void PrintBuffer()
{
// Printing the current state of the buffer
Console.WriteLine(new string(this.buffer.Take(this.size).ToArray()));
}
}class Program
{ static void Main(string[] args)
{
var gapBuffer = new GapBuffer();
Console.WriteLine("Initializing the gap buffer with size 10");
gapBuffer.PrintBuffer();
Console.WriteLine("\nInserting a string to buffer: GEEKSGEEKS");
gapBuffer.Insert("GEEKSGEEKS", 0);
gapBuffer.PrintBuffer();
Console.WriteLine("\nInserting a string to buffer: FOR");
gapBuffer.Insert("FOR", 5);
gapBuffer.PrintBuffer();
Console.WriteLine("\nDeleting character at position 5");
gapBuffer.Deletion(5);
gapBuffer.PrintBuffer();
Console.WriteLine("\nDeleting character at position 6");
gapBuffer.Deletion(6);
gapBuffer.PrintBuffer();
Console.WriteLine("\nDeleting character at position 5");
gapBuffer.Deletion(5);
gapBuffer.PrintBuffer();
Console.WriteLine("\nInserting a string to buffer: HELLO");
gapBuffer.Insert("HELLO", 0);
gapBuffer.PrintBuffer();
}
} |
Javascript
class GapBuffer { constructor() {
// Initializing the gap buffer
this.buffer = Array(50).fill('_');
this.gapSize = 10;
this.gapLeft = 0;
this.gapRight = this.gapSize - 1;
this.size = 10;
}
grow(k, position) {
// Increasing the size of the gap
let a = this.buffer.slice(position, this.size);
this.buffer.splice(position, this.size - position, ...Array(k).fill('_'));
this.buffer.splice(position + k, a.length, ...a);
this.size += k;
this.gapRight += k;
}
left(position) {
// Moving the gap to the left
while (position < this.gapLeft) {
this.gapLeft--;
this.gapRight--;
this.buffer[this.gapRight + 1] = this.buffer[this.gapLeft];
this.buffer[this.gapLeft] = '_';
}
}
right(position) {
// Moving the gap to the right
while (position > this.gapLeft) {
this.gapLeft++;
this.gapRight++;
this.buffer[this.gapLeft - 1] = this.buffer[this.gapRight];
this.buffer[this.gapRight] = '_';
}
}
moveCursor(position) {
// Moving the cursor to the desired position
if (position < this.gapLeft) {
this.left(position);
} else {
this.right(position);
}
}
insert(input, position) {
// Inserting a string at a given position
let len_input = input.length;
let i = 0;
if (position != this.gapLeft) {
this.moveCursor(position);
}
while (i < len_input) {
if (this.gapRight == this.gapLeft) {
let k = 10;
this.grow(k, position);
}
this.buffer[this.gapLeft] = input[i];
this.gapLeft++;
i++;
position++;
}
}
deletion(position) {
// Deleting a character at a given position
if (position + 1 != this.gapLeft) {
this.moveCursor(position + 1);
}
this.gapLeft--;
this.buffer[this.gapLeft] = '_';
}
printBuffer() {
// Printing the current state of the buffer
console.log(this.buffer.slice(0, this.size).join(' '));
}
}// Main function to demonstrate the gap buffer operationslet gapBuffer = new GapBuffer();
console.log("Initializing the gap buffer with size 10");
gapBuffer.printBuffer();console.log("\nInserting a string to buffer: GEEKSGEEKS");
gapBuffer.insert("GEEKSGEEKS", 0);
gapBuffer.printBuffer();console.log("\nInserting a string to buffer: FOR");
gapBuffer.insert("FOR", 5);
gapBuffer.printBuffer();console.log("\nDeleting character at position 5");
gapBuffer.deletion(5);gapBuffer.printBuffer();console.log("\nDeleting character at position 6");
gapBuffer.deletion(6);gapBuffer.printBuffer();console.log("\nDeleting character at position 5");
gapBuffer.deletion(5);gapBuffer.printBuffer();console.log("\nInserting a string to buffer: HELLO");
gapBuffer.insert("HELLO", 0);
gapBuffer.printBuffer(); |
Output
Initializing the gap buffer with size 10 _ _ _ _ _ _ _ _ _ _ Inserting a string to buffer: GEEKSGEEKS Output: G E E K S G E E K S _ _ _ _ _ _ _ _ _ _ Inserting a string to buffer: FOR Output: G E ...
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