<![CDATA[//stack using linked list
#include <stdio.h>
#include <stdlib.h>
struct node
{
int info;
struct node *ptr;
}
*top,*top1,*temp;
int topelement();
void push(int data);
void pop();
void empty();
void display();
void destroy();
void stack_count();
void create();
int count = 0;
void main()
{
int no, ch, e;
printf("\n 1 - Push");
printf("\n 2 - Pop");
printf("\n 3 - Top");
printf("\n 4 - Empty");
printf("\n 5 - Exit");
printf("\n 6 - Dipslay");
printf("\n 7 - Stack Count");
printf("\n 8 - Destroy stack");
create();
while (1)
{
printf("\n Enter choice : ");
scanf("%d", &ch);
switch (ch)
{
case 1: printf("Enter data : ");
scanf("%d", &no);
push(no);
break;
case 2: pop();
break;
case 3: if (top == NULL)
printf("No elements in stack");
else
{
e = topelement();
printf("\n Top element : %d", e);
}
break;
case 4: empty();
break;
case 5: exit(0);
case 6: display();
break;
case 7: stack_count();
break;
case 8: destroy();
break;
default : printf(" Wrong choice, Please enter correct choice "); break;
}
}
}
/* Create empty stack */
void create()
{
top = NULL;
}
/* Count stack elements */
void stack_count()
{
printf("\n No. of elements in stack : %d", count); }
/* Push data into stack */
void push(int data)
{
if (top == NULL)
{
top =(struct node *)malloc(1*sizeof(struct node));
top->ptr = NULL;
top->info = data;
}
else
{
temp =(struct node *)malloc(1*sizeof(struct node));
temp->ptr = top;
temp->info = data;
top = temp;
}
count++;
}
/* Display stack elements */
void display()
{
top1 = top;
if (top1 == NULL)
{
printf("Stack is empty"); return;
}
while (top1 != NULL)
{
printf("%d ", top1->info);
top1 = top1->ptr;
}
}
/* Pop Operation on stack */
void pop()
{
top1 = top;
if (top1 == NULL)
{
printf("\n Error : Trying to pop from empty stack");
return;
}
else top1 = top1->ptr;
printf("\n Popped value : %d", top->info);
free(top);
top = top1;
count--;
}
/* Return top element */
int topelement()
{
return(top->info);
} /* Check if stack is empty or not */
void empty()
{
if (top == NULL)
printf("\n Stack is empty");
else
printf("\n Stack is not empty with %d elements", count);
}
/* Destroy entire stack */
void destroy()
{
top1 = top;
while (top1 != NULL)
{
top1 = top->ptr;
free(top);
top = top1;
top1 = top1->ptr;
}
free(top1);
top = NULL;
printf("\n All stack elements destroyed");
count = 0;
}]]>
