Question

Exercise 2 Add a contains instance method to the IntList class, so that x. contains (n) returns true if the int value n occurs in the IntList x and returns false otherwise.

public class ConsCell
{
private int head;
private ConsCell tail;
public ConsCell(int h, ConsCell t)
{
head = h;
tail = t;
}
public int getHead()
{
return head;
}
public ConsCell getTail()
{
return tail;
}
public void setTail(ConsCell t)
{
tail = t;
}
}

public class IntList
{
private ConsCell start;
public IntList (ConsCell s)
{
start = s;
}
public IntList cons(int h)
{
return new IntList(new ConsCell(h, start));
}
public int length()
{
int len = 0;
ConsCell cell = start;
while (cell != null)
{
len++;
cell = cell.getTail();
}
return len;
}
public void print()
{
System.out.print("[");
ConsCell a = start;
while(a != null)
{
System.out.print(a.getHead());
a = a.getTail();
if(a != null)
System.out.print(",");
}
System.out.println("]");
}
//exercise 5
public IntList reverse()
{
IntList Reverselist = new IntList(null);
ConsCell begin = start;
while (begin != null) {
Reverselist = Reverselist.cons(begin.getHead());
begin = begin.getTail();
}
return Reverselist;
}
}

public class Driver
{
public static void main (String[] args)
{
IntList a = new IntList (null);
IntList b = a.cons(2);
IntList c = b.cons(1);
IntList d = c.reverse();
int x = a.length() + b.length() + c.length();
a.print();
b.print();
c.print();
d.print();
System.out.println(x);
}
}

Answer 1

The defination and implementation of the required method :

public boolean contains(int n)

{
ConsCell cell = start;
while (cell != null)
{
if(cell.h==n)

return true;
cell = cell.getTail();
}
return false;

}