#include<stdio.h>
#include<stdlib.h>
#include<conio.h>
#define MAX 10
int stack[MAX],top = -1;
void push();
int pop();
int peek();
void display();
void change();
int length();
int middle_ele();
void main()
{
int ch;
while(1)
{
printf("\n1.push \n2.pop \n3.peek \n4.display \n5.change \n6.length \n7.middle_element \n8.exit\n");
printf("\nenter the choice : ");
scanf("%d",&ch);
switch(ch)
{
case 1: push(); break;
case 2: pop(); break;
case 3: peek(); break;
case 4: display(); break;
case 5: change(); break;
case 6: length(); break;
case 7: middle_ele(); break;
case 8: exit(0);
default : printf("\n invalid choice\n\n");
}
}
}
void push()
{
int data;
printf("enter the data : ");
scanf("%d",&data);
if(top==MAX-1)
{
printf("\n stack is full");
}
else
{
top++;
stack[top]=data;
printf("%d is inserted.\n",data);
}
}
int pop()
{
if(top==-1)
{
printf("stack is empty\n");
}
else
{
printf("%d is deleted.\n ",stack[top]);
top--;
}
}
int peek()
{
if(top==-1)
{
printf("stack in empty.\n");
}
else
{
printf("%d is peek element.",stack[top]);
}
}
void display()
{
int i;
if(top==-1)
{
printf("stack is empty");
}
else
{
printf("stack elements are :\t");
for(i=0;i<=top;i++)
{
printf("%d\t",stack[i]);
}
}
}
void change()
{
int p,ele;
printf("enter the position where you wants to change the element :");
scanf("%d",&p);
if(top-p<-1)
{
printf("stack is underflow.\n");
}
else
{
printf("enter the new element : ");
scanf("%d",&ele);
stack[p-1]=ele;
printf("~new element %d is inserted: ",stack[p-1]);
}
}
int length()
{
int count=0,i;
for(i=0;i<=top;i++)
{
count=count+1;
}
printf("Length of the stack is : %d\n",count);
return count;
}
int middle_ele()
{
int n,ele,ele1,ele2;
if(length()%2==0)
{
n=length()/2;
ele1 = stack[n-1];
ele2 = stack[n];
printf("Middle element's of the stack are : %d %d\n ",ele1,ele2);
}
else
{
n=length()/2;
ele = stack[n];
printf("Middle element of the stack is : %d\n",ele);
}
}
