This document implements a stack using a singly linked list in C. It defines a node structure with an info field and pointer to the next node. Functions are created to push, pop and display elements on the stack. Push adds a new node to the front of the list, pop removes the front node and frees memory. Display traverses the list and prints elements. The main function provides a menu to test the stack operations and uses a switch to call the appropriate function.

1. Er. Ganesh Ram Suwal
/***** STACK IMPLEMENTATION USING SINGLY LINKED LIST *****/
#include <stdio.h>
#include <conio.h>
#include <stdlib.h>
#include <alloc.h>
/* Global Variable */
int data;
/* Function Prototype */
void push();
void pop();
void display();
/* Structure For Node */
struct node
{
int info;
struct node *pnext;
};
struct node *pfirst,*pnew,*pthis;
void main()
{
clrscr();
int choice = 0;
printf("n********* Stack Operations using Linked List *********n");
printf("---------------------------------------------------------------------");
while(choice != 4)
{
printf("n1.Pushn2.Popn3.Shown4.Exit");
printf("nEnter your choice : ");
scanf("%d",&choice);
switch(choice)
{
case 1:push();
break;
case 2:pop();
break;
case 3:display();
break;
case 4:printf("Exiting....");
break;
default:printf("nSORRY !!! Please Enter valid choice ");
} // End of switch Statement
} // End of while loop
} // End main function
/* PUSH function */
void push()
{
printf("n*********************************************************n");
pnew = (struct node*)malloc(sizeof(struct node));

2. Er. Ganesh Ram Suwal
if(pnew == NULL)
{
printf("SORRY ! Unable to PUSH element");
}
else
{
printf("Enter data : ");
scanf("%d",&data);
pnew->info = data;
if(pfirst == NULL)
{
pnew->pnext = NULL;
pfirst = pnew;
}
else
{
pnew->pnext = pfirst;
pfirst = pnew;
}
printf("The PUSHED element = %d",pfirst->info);
}
printf("n*********************************************************n");
}
/* POP Function */
void pop()
{
printf("n*********************************************************n");
if (pfirst == NULL)
{
printf(" SORRY there is no data in STACK (STACK UNDERFLOW)");
}
else
{
data = pfirst->info;
pthis = pfirst;
pfirst = pfirst->pnext;
free(pthis);
printf("The POPED element = %d",data);
}
printf("n*********************************************************n");
}
void display()
{
int i;
printf("n*********************************************************n");
if(pfirst == NULL)
{
printf(" Stack is empty ");
}
else
{
pthis = pfirst;

3. Er. Ganesh Ram Suwal
printf("The element in the STACK: ");
while(pthis != NULL)
{
printf("%d ",pthis->info);
pthis = pthis->pnext;
}
}
printf("n*********************************************************n");
}

4. Er. Ganesh Ram Suwal

5. Er. Ganesh Ram Suwal