How do you reverse a singly linked list - iterative method?

This program demonstrates how to reverse a singly linked list.

It uses iterative method (simplest way and easy to understand) for doing so.

You can compile this program on bOtskOOl Free Online C/C++ Compiler

SOURCE CODE

#include <stdio.h>

#include <stdlib.h>

// Variables

typedef struct node

{

int value;

struct node *next;

}mynode;

// Globals (not required, though).

mynode *head, *tail, *temp;

// Functions

void add(int value);

void iterative_reverse();

void print_list();

// The main() function

int main()

{

head=(mynode *)0;

// Construct the linked list.

add(1);

add(2);

add(3);

//Print it

print_list();

// Reverse it.

iterative_reverse();

//Print it again

print_list();

return(0);

}

// The reverse function

void iterative_reverse()

{

mynode *p, *q, *r;

if(head == (mynode *)0)

{

return;

}

p = head;

q = p->next;

p->next = (mynode *)0;

while (q != (mynode *)0)

{

r = q->next;

q->next = p;

p = q;

q = r;

}

head = p;

}

// Function to add new nodes to the linked list

void add(int value)

{

temp = (mynode *) malloc(sizeof(struct node));

temp->next=(mynode *)0;

temp->value=value;

if(head==(mynode *)0)

{

head=temp;

tail=temp;

}

else

{

tail->next=temp;

tail=temp;

}

}

// Function to print the linked list.

void print_list()

{

printf("\n\n");

for(temp=head; temp!=(mynode *)0; temp=temp->next)

{

printf("[%d]->",(temp->value));

}

printf("[NULL]\n\n");

}

Output

The above OUTPUT was generated by bOtskOOl Online Compiler - Try it out now>>

Download Source Code