99999999999999


#include <stdio.h>
#include <malloc.h>
struct node
{
struct node *prev;
struct node *next;
int data;
};
struct node *start=NULL;
void traverse();
int main(void)
{
int n,i,item;
struct node *ptr,*temp;
printf("Enter how many nodes:");
scanf("%d", &n);
for(**0;i<n;i++)
{
printf("Enter value:");
scanf("%d", &item);
ptr=(struct node*)malloc(sizeof(struct node));
ptr->data=item;
if(start==NULL)
{
ptr->next=NULL;
ptr->prev=NULL;
start=ptr;
}
else
{
temp=start;
while(temp->next!=NULL)
{
temp=temp->next;
}
temp->next=ptr;
ptr->prev=temp;
ptr->next=NULL;
}
}
printf("Printing values in forward direction..............\n");
ptr=start;
while(ptr!=NULL)
{
printf("%d->",ptr->data);
ptr=ptr->next;
}
ptr=start;
while(ptr->next!=NULL)
{
ptr=ptr->next;
}
printf("\nPrinting values backward direction...\n");
while(ptr!=NULL)
{
printf("%d->",ptr->data);
ptr=ptr->prev;
}
return 0;
}












10













#include <stdio.h>
#define maxsize 50
int stack[maxsize],top=-1;
void create();
void display();
void pop();
void push();
int main()
{
int ch,top=-1;
while(1)
{
printf("\n1.Create\n");
printf("2.Display\n");
printf("3.Push\n");
printf("4.Pop\n");
printf("5.Exit\n");
printf("Enter your choice:");
scanf("%d",&ch);
if(ch==5)
{
return 0;
}
switch(ch)
{
case 1:
create();
break;
case 2:
display();
break;
case 3:
push();
break;
case 4:
pop();
break;
}
}
}
void create()
{
int che;
do
{
top++;
printf("Input element:");
scanf("%d",&stack[top]);
printf("Press 1 if more data other wise 0:");
scanf("%d",&che);
}while(che==1);
return;
}
void display()
{
int i;
if(top==-1)
{
printf("Stack is empty");
}
for(**top;i>=0;i--)
{
printf("%d\t",stack[i]);
}
return;
}
void push()
{
int m;
if(top==maxsize-1)
{
printf("Overflow");
return;
}
top++;
printf("Enter new element:");
scanf("%d",&m);
stack[top]=m;
return;
}
void pop()
{
if(top==-1)
{
printf("Underflow");
return;
}
printf("%d is deleted",stack[top]);
stack[top]='\0';
top--;
return;
}






1111111111111111111111111





#include<stdio.h>
#define maxsize 50
int stack[maxsize],top=1;
void create();
void display();
void pop();
void push();
int main()
{
int ch,top=1;
while(1)
{
printf("\n1.create\n");
printf("2.display\n");
printf("3.push\n");
printf("4.pop\n");
printf("5.exit\n");
printf("enter your choice:");
scanf("%d",&ch);
if(ch==5)
{
return 0;
}
switch(ch)
{
case 1:
create();
break;
case 2:
display();
break;
case 3:
push();
break;
case 4:
pop();
break;
}
}
}
void creator()
{
int che;
do
{
top++;
printf("input element:");
scanf("%d",&stack[top]);
printf("press 1 if more data otherwise 0:");
scanf("%d",&che);
}
while(che==1);
return;
}
void display()
{
int i;
if(top==-1)
{
printf("stack is empty");
}
for(**top;1>=0;i--)
{
printf("%d\t",stack[i]);
}
return;
}
void push()
{
int m;
if(top==maxsize-1)
{
printf("overflow");
return;
}
top++;
printf("enter new element:");
scanf("%d",&m);
stack[top]=m;
return;
}
void pop()
{
if (top==-1)
{
printf("underflow");
return;
}
printf("%d is deleted",stack[top]);
stack[top]='\0';
top--;
return;
}







122222222222222














#include<stdio.h> 
#include<ctype.h>
int stack[20];
int top=-1;
void push(int);
int pop();
int main(void)
{
char exp[20],*e;
int n1,n2,n3,num;
printf("enter the postfix expression:");
scanf("%s",exp);
e=exp;
while(*e!='\0')
{
if(isdigit(*e))
{
num=*e-48;
push(num);
}
else
{
n1=pop();
n2=pop();
switch(*e)
{
case'+':
n3=n1+n2;
break;
case'-':
n3=n2-n1;
break;
case'*':
n3=n2*n1;
break;
case'/':
n3=n2/n1;
break;
}
push(n3);
}
e++;
}
printf("result=%d",pop());
return 0;
}
void push(int x)
{
stack[++top]=x;
}
int pop()
{
return stack[top--];
}







133333333333





#include<stdio.h>
#define maxsize 50
int queue[maxsize],front=-1,rear=-1;
void push();
void pop();
void display();
int main(void)
{
int ch,c=1;
while(1)
{
printf("\n1.push");
printf("\n2.pop");
printf("\n3.display");
printf("\n4.exit");
printf("\n enter your choice:");
scanf("%d",&ch);
if(ch==4)
{
return 0;
}
switch(ch)
{
case 1:
push();
break;
case 2:
pop();
break;
case 3:
display();
break;
}
}
return 0;
}
void push()
{
int a;
printf("enter value:");
scanf("%d",&a);
if(rear==maxsize-1);
{
printf("overflow");
return;
}
rear++;
queue[rear]=a;
if(front==-1)
{
front=0;
}
return;
}
void pop()
{
int a;
if (front==-1)
{
printf("queue empty");
return;
}
printf("%d is deleted",queue[front]);
a=queue[front];
queue[front]=0;
if(front=rear=-1)
{
front=rear=-1;
}
else
{
front++;
}
return;
}
void display()
{
int t;
if(front==-1)
{
printf("queue is empty");
}
else
{
printf("queue elements are...\n");
for(t=front;t<=rear;t++)
{
printf("%d/t",queue[t]);
}
}
return;
}