Question

CONVERT THE FOLLOWING C/C++ PROGRAM INTO JAVA:

//LinkedString.h

#pragma once
#include<iostream>
#include<string>
using namespace std;
//declare a node datastruct
struct Node
{
   char c;
   Node *next;
};
class LinkedString
{
   Node *head;
public:
   LinkedString();
   LinkedString(char[]);
   LinkedString(string);
   char charAt(int) const;
   string concat(const LinkedString &obj) const;
   bool isEmpty() const;
   int length() const;
   LinkedString substring(int, int) const;
   //added helper function to add to linekd list
private:
   void add(char c);
};

==============================================

//LinkedString.cpp

#include"LinkedString.h"

LinkedString::LinkedString()
{
   head = NULL;
}
LinkedString::LinkedString(char s[])
{
   Node *newNode, *cur = head;

   for (int i = 0; s[i] != '\0'; i++)
   {
       newNode = new Node;
       newNode->c = s[i];
       newNode->next = NULL;
       if (head == NULL)
       {
           //assign newNode to head
           head = newNode;
       }
       else
       {
           //traverse through list and add new char at end
           cur = head;
           while (cur->next != NULL)
               cur = cur->next;
           cur->next = newNode;
       }
   }
}
LinkedString::LinkedString(string s)
{
   Node *newNode, *cur = head;
   int n = s.length();
   for (int i = 0; i<n; i++)
   {
       newNode = new Node;
       newNode->c = s[i];
       newNode->next = NULL;
       if (head == NULL)
       {
           //assign newNode to head
           head = newNode;
       }
       else
       {
           //traverse through list and add new char at end
           cur = head;
           while (cur->next != NULL)
               cur = cur->next;
           cur->next = newNode;
       }
   }
}
char LinkedString::charAt(int i) const
{
   Node *cur = head;
   int count = 0;
   if (i < 0 && i >= length())
   {
       cout << "Index error!!"<<endl;
       return 0;
   }
   while (cur != NULL)
   {
      
       if (count == i)
           break;
       ++count;
       cur = cur->next;
   }
   if (count >= 0)
       return cur->c;
   else
       return count;
}
string LinkedString::concat(const LinkedString &obj) const
{
   string constr = "";
   for (int i = 0; i < length(); i++)
   {
       constr += charAt(i);
   }
   for (int i = 0; i < obj.length(); i++)
   {
       constr += obj.charAt(i);
   }
   return constr;
}
bool LinkedString::isEmpty() const
{
   if (head == NULL)
       return true;
   return false;
}
int LinkedString::length() const
{
   Node *cur = head;
   int count = 0;
   while (cur != NULL)
   {
       ++count;
       cur = cur->next;
   }
   return count;
}
void LinkedString::add(char c)
{
   Node *cur = head, *newNode;
   newNode = new Node;
   newNode->c = c;
   newNode->next = NULL;
   if (head == NULL)
   {
       head = newNode;
   }
   else
   {
       cur = head;
       while (cur->next != NULL)
           cur = cur->next;
       cur->next = newNode;
   }
}
LinkedString LinkedString::substring(int j, int k) const
{
   LinkedString ret;
   Node *cur = head;
   int count = 0;
   while (cur != NULL)
   {
       if (j == count)
       {
           break;
       }
       ++count;
       cur = cur->next;
   }

   while (count++ <=k)
   {
       if (cur == NULL)
           break;
       ret.add(cur->c);
       cur = cur->next;
   }
   return ret;
}

=============================

//Main.cpp

#include<iostream>
#include"LinkedString.h"

using namespace std;

int main()
{
   char str[] = "Hello World!!";
   //declare LinkedString object
   LinkedString s1("Test"),s2(str);
   //display linekd LinkedString
   cout << "Linked string s1: ";
   for (int i = 0; i < s1.length(); i++)
   {
       cout << s1.charAt(i);
   }
   cout << endl;
   cout<<"Concatinated string : "<<s1.concat(s2)<<endl;
   cout << "Substring: ";
   LinkedString substr = s2.substring(6, 11);
   //print substr
   for (int i = 0; i < substr.length(); i++)
   {
       cout << substr.charAt(i);
   }
}

/*Output
Linked string s1: Test
Concatinated string : TestHello World!!
Substring: World!
*/

Answer 1

Dear Student,

Converting above program in JAVA.

/********************************** IN JAVA ********************************/

class Node
{
char c;
Node next;
}

//class LinkedString
class LinkedString
{
Node head;

public LinkedString(){
head = null;
}
public LinkedString(char s[]){

Node newNode, cur = head;
for (char i: s)
{
newNode = new Node();
newNode.c = i;
newNode.next = null;
if (head == null)
{
//assign newNode to head
head = newNode;
}
else
{
//traverse through list and add new char at end
cur = head;
while (cur.next != null)
cur = cur.next;
cur.next = newNode;
}
}
}
public LinkedString(String s){
Node newNode, cur = head;
int n = s.length();
char ch[] = s.toCharArray();
for (char i:ch)
{
newNode = new Node();
newNode.c = i;
newNode.next = null;
if (head == null)
{
//assign newNode to head
head = newNode;
}
else
{
//traverse through list and add new char at end
cur = head;
while (cur.next != null)
cur = cur.next;
cur.next = newNode;
}
}
}
public char charAt(int i){
Node cur = head;
int count = 0;
if (i < 0 && i >= length())
{
System.out.println("Index error!!");
return 0;
}
while (cur != null)
{
if (count == i)
break;
++count;
cur = cur.next;
}
return cur.c;
}

public String concat(LinkedString obj){
String constr = "";
for (int i = 0; i < length(); i++)
{
constr += charAt(i);
}
for (int i = 0; i < obj.length(); i++)
{
constr += obj.charAt(i);
}
return constr;
}

public boolean isEmpty(){
if (head == null)
return true;
return false;
}

//claculating length of list
public int length(){
Node cur = head;
int count = 0;
while (cur != null)
{
++count;
cur = cur.next;
}
return count;
}

public LinkedString substring(int j, int k){
LinkedString ret = new LinkedString();
Node cur = head;
int count = 0;
while (cur != null)
{
if (j == count)
{
break;
}
++count;
cur = cur.next;
}
  
while (count++ <= k)
{
if (cur == null)
break;
ret.add(cur.c);
cur = cur.next;
}
return ret;
}

//added helper function to add to linekd list

private void add(char c){
Node cur = head, newNode;
newNode = new Node();
newNode.c = c;
newNode.next = null;
if (head == null)
{
head = newNode;
}
else
{
cur = head;
while (cur.next != null)
cur = cur.next;
cur.next = newNode;
}
}
}

public class Main
{
   public static void main(String[] args) {
  
char str[] = "Hello World!!".toCharArray();
//declare LinkedString object
LinkedString s1= new LinkedString("Test");
LinkedString s2 = new LinkedString(str);
//display linekd LinkedString
System.out.print("Linked string s1: ");
for (int i = 0; i < s1.length(); i++)
{
System.out.print(s1.charAt(i));
}
System.out.println();
System.out.println("Concatinated string : " + s1.concat(s2));
System.out.print("Substring: ");
LinkedString substr = s2.substring(6, 11);
//print substr
for (int i = 0; i < substr.length(); i++)
{
System.out.print(substr.charAt(i));
}
}
}