reverse_a_linked_list.cpp File Reference

Implementation of Reversing a single linked list More...

#include <cassert>
#include <iostream>
#include <memory>
#include <new>

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Classes
class	data_structures::linked_list::Node
class	data_structures::linked_list::list

Namespaces
namespace	data_structures
	Data Structures algorithms.
namespace	linked_list
	Functions for singly linked list algorithm.

Functions
static void	test ()
	Self-test implementations. More...
int	main ()
	Main function. More...

Detailed Description

Implementation of Reversing a single linked list

The linked list is a data structure used for holding a sequence of values, which can be added, displayed, reversed, or removed.

Algorithm

Values can be added by iterating to the end of a list (by following the pointers) starting from the first link. Whichever link points to null is considered the last link and is pointed to the new value.

Linked List can be reversed by using 3 pointers: current, previous, and next_node; we keep iterating until the last node. Meanwhile, before changing to the next of current, we store it in the next_node pointer, now we store the prev pointer in the current of next, this is where the actual reversal happens. And then we move the prev and current pointers one step forward. Then the head node is made to point to the last node (prev pointer) after completion of an iteration.

A graphic explanation and view of what's happening behind the scenes

Function Documentation

main()

int main

(

void

)

Main function.

Returns

0 on exit

           {
    test();  // run self-test implementations
    return 0;
}

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test()

static void test ( )

static

Self-test implementations.

Returns

void

                   {
    data_structures::linked_list::list L;
    // 1st test
    L.insert(11);
    L.insert(12);
    L.insert(15);
    L.insert(10);
    L.insert(-12);
    L.insert(-20);
    L.insert(18);
    assert(L.top() == 11);
    assert(L.last() == 18);
    L.reverseList();
    // Reversal Testing
    assert(L.top() == 18);
    assert(L.traverse(1) == -20);
    assert(L.traverse(2) == -12);
    assert(L.traverse(3) == 10);
    assert(L.traverse(4) == 15);
    assert(L.traverse(5) == 12);
    assert(L.last() == 11);
    std::cout << "All tests have successfully passed!" << std::endl;
}

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