How do you implement stack using singly linked list?

Answer 1

struct node

{

int info;

struct node *link;

} *top=NULL;

int main()

{

int choice;

while(1)

{ printf("1.Push\n");

printf("2.Pop\n");

printf("3.Display\n");

printf("4.Quit\n");

printf("Enter your choice : ") ;

scanf("%d", &choice);

switch(choice)

{

case 1:

push();

break;

case 2:

pop();

break;

case 3:

display();

break;

case 4:

exit(1);

default :

printf("Wrong choice\n");

}/*End of switch */

}/*End of while */

return 0;

}/*End of main() */

void push()

{

struct node *tmp;

int pushed_item;

tmp = malloc(sizeof(struct node));

printf("Input the new value to be pushed on the stack : ");

scanf("%d",&pushed_item);

tmp->info=pushed_item;

tmp->link=top;

top=tmp;

}/*End of push()*/

void pop()

{

struct node *tmp;

if(top == NULL)

printf("Stack is empty\n");

else

{ tmp=top;

printf("Popped item is %d\n",tmp->info);

top=top->link;

free(tmp);

}

}/*End of pop()*/

void display()

{ struct node *ptr;

ptr=top;

if(top==NULL)

printf("Stack is empty\n");

else

{

printf("Stack elements :\n");

while(ptr!= NULL)

{

printf("%d\n",ptr->info);

ptr = ptr->link;

}/*End of while */

}/*End of else*/

}/*End of display()*/

Answer 2

Stack push allocates an element, copies the data into the element, and inserts it at the head of the list. It throws a memory full exception when it cannot allocate an element.

Stack pop removes and deallocates the element at the head of the list after copying the data from the element. It throws a stack empty exception when the list is found to be empty.

THE PROGRAM GOES LIKE THIS:

//linked list implementation of stack

#include

#include

#include

#include

struct node

{

char info[15];

struct node *link;

}*start=NULL;

int push()

{

struct node *temp;

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

printf("\nEnter the string::\n");

scanf("%s",temp->info);

temp->link=start;

start=temp;

return 0;

}

int pop()

{

struct node *temp;

if(start==NULL)//empty stack

{

printf("\nUnderflow!\n");

return 0;

}

temp=start;

start=temp->link;

printf("\nString popped is:%s\n",temp->info);

free(temp);

return 0;

}

int display()

{

struct node *temp;

if(start==NULL)//empty stack

{

printf("\nEmpty Stack!\n");

return 0;

}

temp=start;

printf("\nThe stack is:\n");

while(temp!=NULL)

{

printf("%s\n",temp->info);

temp=temp->link;

}

return 0;

}

int main()

{

int choice;

while(1)

{

printf("\nLinked list implementation of stack:\nWhat do u wanna do?:\n1.Push\n2.Pop\n3.Display\n4.Exit\nEnter ur choice........\n");

scanf("%d",&choice);

switch(choice)

{

case 1:

push();

break;

case 2:

pop();

break;

case 3:

display();

break;

case 4:

exit(1);

break;

default:

printf("\nSoooooory!!!!Wrong choice .plz try again..\n");

}

}//end of while

return 0;

}

Answer 3

One way to implement a stack using a list is to use a forward list (a uni-directional or singly-linked list), where all insertions and extractions occur at the head. Each node points to the next so the list only needs to maintain a pointer to the current head of the list. The memory overhead is minimal (one pointer per node, plus one pointer to keep track of the head node), however there will be a slight performance penalty as a result of the inherent indirection as well as the need to allocate new memory for each new node. The latter problem can be addressed by using your own memory allocator to reserve one or more "pools" of memory within which to construct new nodes.