Problem: Stack Using Linked List
#include<stdio.h>
#include<conio.h>
#include<stdlib.h>
struct node
{
int data;
struct node *nextlink;
struct node *prevlink;
}*top=NULL,*temp,*new1;
void push();
void pop();
void display();
void main()
{
int num;
clrscr();
while(1)
{
printf("\n*** STACK OPERATIONS LL ***\n");
printf("1.PUSH\n2.POP\n3.DISPLAY\n4.EXIT\n");
printf("Enter your Choice:");
scanf("%d",&num);
switch(num)
{
case 1:
push();
break;
case 2:
pop();
break;
case 3:
display();
break;
case 4:
exit(0);
break;
default:
printf("\nWrong Choice!!");
break;
}
}
}
void push()
{
int n;
new1=(struct node*)malloc(sizeof(struct node));
printf("Enter the value:");
scanf("%d",&n);
new1->data=n;
new1->prevlink=NULL;
new1->nextlink=NULL;
if(top==NULL)
{
top=new1;
}
else
{
top->nextlink=new1;
new1->prevlink=top;
top=new1;
}
}
void pop()
{
if(top==NULL)
{
printf("\nStack is Empty!!");
}
else if(top->prevlink==NULL && top->nextlink==NULL)
{
printf("\n%d is a deleted element",top->data);
free(top);
top=NULL;
}
else
{
temp=top;
top=temp->prevlink;
printf("\n%d is a deleted element",temp->data);
free(temp);
top->nextlink=NULL;
}
}
void display()
{
if(top==NULL)
{
printf("\nSTACK IS EMPTY!!\n");
}
else
{
temp=top;
while(temp->prevlink!=NULL)
{
printf("%d\n",temp->data);
temp=temp->prevlink;
}
printf("%d\n",temp->data);
}
}
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