C Program to Reverse a Stack without Recursion

This C program, using iteration, reverses a stack content. Stack here is represented using a linked list. A linked list is an ordered set of data elements, each containing a link to its successor.

Here is the source code of the C program to display a linked list in reverse. The C program is successfully compiled and run on a Linux system. The program output is also shown below.

```
/*
```

 * C Program to Reverse a Stack without using Recursion

```
 */
```
```
#include <stdio.h>
```
```
#include <stdlib.h>
```
```
 
```
```
struct node
```
```
{
```
```
    int a;
```
```
    struct node *next;
```
```
};
```
```
 
```
```
void generate(struct node **);
```
```
void display(struct node *);
```
```
void stack_reverse(struct node **);
```
```
void delete(struct node **);
```
```
 
```
```
int main()
```
```
{
```
```
    struct node *head = NULL;
```
```
 
```
```
    generate(&head);
```

    printf("\nThe sequence of contents in stack\n");

```
    display(head);
```

    printf("\nInversing the contents of the stack\n");

```
    stack_reverse(&head);
```

    printf("\nThe contents in stack after reversal\n");

```
    display(head);
```
```
    delete(&head);
```
```
    return 0;
```
```
}
```
```
 
```
```
void stack_reverse(struct node **head)
```
```
{
```
```
    struct node *temp, *prev;
```
```
 
```
```
    if (*head == NULL)
```
```
    {
```

        printf("Stack does not exist\n");

```
    }
```
```
    else if ((*head)->next == NULL)
```
```
    {
```

        printf("Single node stack reversal brings no difference\n");

```
    }
```

    else if ((*head)->next->next == NULL)

```
    {
```
```
        (*head)->next->next = *head;
```
```
        *head = (*head)->next;
```
```
        (*head)->next->next = NULL;
```
```
    }
```
```
    else
```
```
    {
```
```
        prev = *head;
```
```
        temp = (*head)->next;
```
```
        *head = (*head)->next->next;
```
```
        prev->next = NULL;
```
```
        while ((*head)->next != NULL)
```
```
        {
```
```
            temp->next = prev;
```
```
            prev = temp;
```
```
            temp = *head;
```
```
            *head = (*head)->next;
```
```
        }
```
```
        temp->next = prev;
```
```
        (*head)->next = temp;
```
```
    }
```
```
}
```
```
 
```
```
void display(struct node *head)
```
```
{
```
```
    if (head != NULL)
```
```
    {
```
```
        printf("%d  ", head->a);
```
```
        display(head->next);
```
```
    }
```
```
}
```
```
 
```
```
void generate(struct node **head)
```
```
{
```
```
    int num, i;
```
```
    struct node *temp;
```
```
 
```
```
    printf("Enter length of list: ");
```
```
    scanf("%d", &num);
```
```
    for (i = num; i > 0; i--)
```
```
    {
```

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

```
        temp->a = i;
```
```
        if (*head == NULL)
```
```
        {
```
```
            *head = temp;
```
```
            (*head)->next = NULL;
```
```
        }
```
```
        else
```
```
        {
```
```
            temp->next = *head;
```
```
            *head = temp;
```
```
        }
```
```
    }
```
```
}
```
```
 
```
```
void delete(struct node **head)
```
```
{
```
```
    struct node *temp;
```
```
    while (*head != NULL)
```
```
    {
```
```
        temp = *head;
```
```
        *head = (*head)->next;
```
```
        free(temp);
```
```
    }
```
```
}
```

$ cc revstack_iter.c -o revstack_iter
$ a.out
Enter length of list: 8
 
The sequence of contents in stack
1  2  3  4  5  6  7  8  
Inversing the contents of the stack
 
The contents in stack after reversal
8  7  6  5  4  3  2  1

Sanfoundry Global Education & Learning Series – 1000 C Programs.

Here’s the list of Best Books in C Programming, Data-Structures and Algorithms

If you wish to look at other example programs on Stacks & Queues, go to C Programming Examples on Stacks & Queues. If you wish to look at programming examples on all topics of C, go to C Programming Examples.

« Prev - C Program to Implement a B Tree

» Next - C Program to Reverse a Linked List using Recursion

Related Posts:

Check Computer Science Books
Apply for Computer Science Internship
Check Programming Books
Check Data Structure Books
Practice Design & Analysis of Algorithms MCQ

Recommended Articles: