Question

c++ just one file for all of it.

You are to implement a 'list' class to handle a list with general operations. That means you can insert and delete any element anywhere in the list. your list will be an array. the list has no order, except for the order you insert or delete. The methods you are to implement are as given:

constructor methods (two, default and copy constructor, a list to a newly defined list, ie 'list listA(listB)')

empty returns true or false if list is empty or not.

first makes current position at the beginning of the list

last makes current position at the end of a list

prev places current position at the previous element in the list

getpos returns current position or where you are in the list

setpos(int)places current position in a certain position in the list

insertbefore inserts a new element before the current position

insertafter inserts a new element after the current position

getelement returns the one element that current position is pointing to

size returns the size of the list (number of elements in list)

replace(int) replace the current element with a new value

erase deletes the current element

clear makes the list an empty list

overload the operators: <<output, ==, !=, +, +=, =(assignment)

you are to implement the list class using an array. the array can be 20 in size.

you will need to use the 'element type' for 'typing' your data

you will need to use CAPACITY constant for the size of the array, in case we need to change the array size

invariants: the elements in the list are to be left justified with in the array. 'pos' will point to a valid location in the array (ie where data is located.

on insert, 'pos' should point to the element just inserted on insert operations. 'pos' should never be outside of element list.

test the code with a main program.

Answer 1

PROGRAM

#include<iostream>
#include<stdlib.h>
#include <iomanip>

using namespace std;

const int CAPACITY = 20;

template<class T>
class List
{
//private members
private:
   T arr[CAPACITY];
   int num_used;
   int cur_pos;
public:

   //default constructor
   List()
   {
       num_used = 0;
       cur_pos = -1;
   }

   //copy constructor
   List(const List& list)
   {
       num_used = list.num_used;
       for(int i=0; i<num_used; i++)
       {
           arr[i] = list.arr[i];
       }
   }
  
   //returns true or false if list is empty or not.
   bool empty()
   {
       return ((num_used==0)?true:false);
   }
  
   //makes current position at the beginning of the list
   void first()
   {
       cur_pos = 0;
   }
  
   //makes current position at the end of a list
   void last()
   {
       cur_pos = num_used - 1;
   }
  
   //places current position at the previous element in the list
   void prev()
   {
       cur_pos--;
   }
  
   //returns current position or where you are in the list
   int getpos()
   {
       return cur_pos;
   }
  
   //places current position in a certain position in the list
   void setpos(int i)
   {
       if(i>=0 && i<num_used)
           cur_pos = i;
   }
  
   //inserts a new element before the current position
   void insertbefore(int item)
   {      
       for(int i=num_used; i>=cur_pos; i--)
           arr[i+1] = arr[i];
       arr[cur_pos] = item;
       num_used++;
   }
  
   //inserts a new element after the current position
   void insertafter(int item)
   {
       cur_pos++;
       for(int i=num_used; i>=cur_pos; i--)
           arr[i+1] = arr[i];
       arr[cur_pos] = item;
       num_used++;
   }
  
   //returns the one element that current position is pointing to
   T getelement()
   {
       return arr[cur_pos];
   }
  
   //returns the size of the list (number of elements in list)
   int size()
   {
       return num_used;
   }
  
   //replace the current element with a new value
   void replace(T item)
   {
       arr[cur_pos] = item;
   }
  
   //deletes the current element
   T erase()
   {
       T item = arr[cur_pos];
       for(int i=cur_pos; i<num_used-1; i++)
           arr[i] = arr[i+1];
       num_used--;
       return item;
   }
  
   //makes the list an empty list
   void clear()
   {
       num_used = 0;
       cur_pos = -1;
   }
  
   // << operator overloading
   friend ostream& operator<<(ostream &out, const List &list)
   {
       out<<endl<<"[";
       for(int i=0; i<list.num_used; i++)
           out<<list.arr[i]<<" ";
       out<<"]"<<endl;
      
       return out;
   }
  
   // == operator overloading
   bool operator==(const List &list)
   {
       if(num_used!=list.num_used)
           return false;
       for(int i=0; i<num_used; i++)
       {
           if(arr[i]!=list.arr[i])
               return false;
       }
       return true;
   }
  
   // != operator overloading
   bool operator!=(const List &list)
   {
       if(num_used!=list.num_used)
           return true;
       for(int i=0; i<num_used; i++)
       {
           if(arr[i]!=list.arr[i])
               return true;
       }
       return false;
   }
  
   // = operator overloading
   List& operator=(const List &list)
   {
       num_used = list.num_used;
       for(int i=0; i<num_used; i++)
       {
           arr[i] = list.arr[i];
       }
       return *this;
   }
  
   // + operator overloading
   List operator+(const List &b)
   {
       List a;
      
       a.num_used = num_used + b.num_used;
       for(int i=0; i<num_used; i++)
       {
           a.arr[i] = arr[i];
       }
      
       for(int k=0; k<b.num_used; k++)
       {
           a.arr[num_used + k] = b.arr[k];
       }
      
       return a;
   }
  
   // += operator overloading
   List& operator+=(const List &b)
   {
       for(int k=0; k<b.num_used; k++)
       {
           arr[num_used + k] = b.arr[k];
       }
       num_used = num_used + b.num_used;
      
       return *this;
   }
};

int main()
{
   //create objects
   List<int>a;
   List<int> b;
   List<int> c;
  
   //insert elements
   a.insertafter(10);
   a.insertafter(20);
   a.insertafter(30);
   a.insertafter(40);
   a.insertafter(50);
  
   //print a
   cout<<a;
  
   //insert elements
   b.insertafter(60);
   b.insertafter(70);
   b.insertafter(80);
  
   //print b
   cout<<b;
  
   //add two list
   c = a + b;
  
   //print c
   cout<<c;
  
   //clear c
   c.clear();
  
   //assign a to c
   c = a;
  
   //print c
   cout<<c;
  
   //set current position
   c.setpos(2);
  
   //delete an element
   c.erase();
  
   //print c
   cout<<c;
  
   /* Testing */
   List<int> d(a);
  
   cout<<d;
   cout<<boolalpha<<d.empty()<<endl;
  
   d.first();
   cout<<d.getpos()<<endl;
   cout<<d.getelement()<<endl;
  
   d.last();
   cout<<d.getpos()<<endl;
   cout<<d.getelement()<<endl;
  
   d.prev();
   cout<<d.getpos()<<endl;
   cout<<d.getelement()<<endl;
  
   d.insertbefore(90);
   cout<<d;
  
   d.replace(55);
   cout<<d;
  
   cout<<d.erase()<<endl;
   cout<<d;
  
   cout<<(a==d)<<endl;
   cout<<(a!=d)<<endl;
   d+=c;
   cout<<d;
  
   return 0;
}

Sample Output:

[10 20 30 40 50 ]

[60 70 80 ]

[10 20 30 40 50 60 70 80 ]

[10 20 30 40 50 ]

[10 20 40 50 ]

[10 20 30 40 50 ]
false
0
10
4
50
3
40

[10 20 30 90 40 50 ]

[10 20 30 55 40 50 ]
55

[10 20 30 40 50 ]
true
false

[10 20 30 40 50 10 20 40 50 ]

--------------------------------
Process exited after 0.248 seconds with return value 0
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