Reverse a string or linked list using stack.

See complete series on data structures here:

In this lesson, we have described how we can reverse a string or linked list using stack. Reversal is a simple application of stack.

To know about implicit stack, see this video:

Reversal of linked list using recursion:

[yokedici]

"...a warrior should not just possess a weapon, but he must also know when and how to use it." well said bro

[mycodeschool]

Hi Shadman
Data structures is our priority. We publish 2 to 3 videos in a week. So the complete series will take some time.

[suyash.]

so grateful that this person made such a nice library of SUPER HELPFUL content which continues to help so many even after he's no longer here.

[vigneshwarm]

Here is the complete code for 2nd program:


#include<iostream>
#include <stack>
using namespace std;


struct Node
{
int value;
Node *next;
};




void reverse(Node** head){


Node* temp = *head;


if(*head == NULL) return;


stack<struct Node*> s;


// push to stack
while (temp!=NULL)
{
s.push(temp);
temp = temp->next;

}


temp = s.top();
*head = temp;
s.pop();


//reverse
while (!s.empty())
{

temp->next = s.top();

s.pop();
temp = temp->next;
}
temp->next = NULL;


}


void push(Node **head, int value)
{


Node *temphead = *head;


Node *temp = new Node();
temp->value = value;
temp->next = NULL;


if (*head == NULL)
{
*head = temp;
return;
}


while (temphead->next != NULL)
{
temphead = temphead->next;
}
temphead->next = temp;
}


// To print the linked list
void print(Node *head)
{
Node *temp = head;


while (temp != NULL)
{
cout << temp->value << "\n";
temp = temp->next;
}
}


int main(){


Node *head = NULL;


push(&head, 1);
push(&head, 2);
push(&head, 3);


print(head);


reverse(&head);

cout << "rev: "<< "\n";
print(head);


return 0;
}

[nirajabcd]

I really learned a lot from your videos. Thank you so much for your time and effort.

[kalyanroy]

The power of simplicity, which each word of your's enforces is just divine. The way you carry ADT, Implementation & Analysis of Running Time on a nutshell, is simply the best thing that could ever be done in any Planet, on and beyond eternity.

[factwithhunny]

Frnds if you are doing code in C Plz include
<limits.h>
I have tried approx 2 days for this question so plz note this
#include <string.h> for string length
#include<limits.h>

[MinhazulArefinAbtahi]

Thanks for all your efforts. So grateful that these tutorial videos are still here while you are no longer with us. You will always be remembered Harsha Suryanarayana!

[PratikShende]

the teacher is not between us any more ...but his teaching would always be here for years....thanks for making all those videos ..may he is happy wherever he is...

[danhle]

just in case you have any error for implementing the 1st example, check out my code in c++ :

#include <iostream>
#include <stack>
#include <cstring>

using namespace std;

void Reverse(char *C, int n)
{
stack<char> S;
for (int i = 0; i < n; i++)
{
S.push(C[i]);
}
for (int i = 0; i < n; i++)
{
C[i] = S.top();
S.pop();
}
}

int main()
{
char C[51];
cout << "\nEnter a string: ";
cin >> C;
Reverse(C, strlen(C));
cout << "Reversed output: " << C;
cout << "\n";
}

[aswinvishnua]

for using strlen(c), include <cstring> headerfile:
#include <cstring>

[junegirly]

Urs tutorial is too good nd pfcorse ...of ur voice. .it's easy to understand everything..post more videos..on c

[mycodeschool]

Hi Shadman,
Data structures is our priority. We publish 2-3 videos in a week. So, the complete series will take some time.

[vijaydwivedi]

Precious Gift to the world, thanks buddy, CS DOJO approved, BULLDOG MINDSET approved etc etc .

[Stacy]

8:33 closed caption says "space complexity O(n)" while you're correctly saying O(1),
just letting you know

[emrekorkmaz]

I wish you could be my data structure teacher :) thanks for the videos, it helped me a lot :)

[stunner]

Thanks for all the effort you people have put in to make these videos. These are the best. ☺

[smitasingh]

u are ruling on ytube when no any good content where uploaded . Omg this vid is 8 yrs old...can't really think such old and such informative content.

[theilluminati]

how can you switch to C++, I am following C from the start?

[pryakks]

Code in C:

#include<stdio.h>
#include<string.h>
#define MAX_SIZE 101
int A[MAX_SIZE]; //global var
int top=-1;//represent empty stack

void Push(int x){
    if(top == MAX_SIZE-1){
        printf("Error: stack overflow\n");
        return;
    }
    A[++top]= x;
    printf("%c", x);
}
void Pop(){
    if(top == -1){
        printf("Error: stack overflow\n");
        return;
    }
    printf("%c", A[top--]);
}

int main(){
 char str[] ="mycodeschool";
    int len = strlen(str), i;
    printf("Original String : ");
    for(i=0;i<len;i++)
        Push(str[i]);
        printf("\n");
 printf("Reversed String : ");

     for(i=0;i<len;i++)
        Pop();
}