why a list is not used for implementation of stack code example
Example: stack implementation using linked list in c
#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;
}
}
}
void create()
{
top = NULL;
}
void stack_count()
{
printf("\n No. of elements in stack : %d", count);
}
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++;
}
void display()
{
top1 = top;
if (top1 == NULL)
{
printf("Stack is empty");
return;
}
while (top1 != NULL)
{
printf("%d ", top1->info);
top1 = top1->ptr;
}
}
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--;
}
int topelement()
{
return(top->info);
}
void empty()
{
if (top == NULL)
printf("\n Stack is empty");
else
printf("\n Stack is not empty with %d elements", count);
}
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;
}