STACK ADT ARRAY 
AIM:
To write a program for implementing a stack using arrays to perform various operations such as Push, Pop, Stack Empty, Stack full and Display.

ALGORITHM:
1.PUSH:
STEP 1:Create a function push() with argument element to be added.
STEP 2:Assign the new element in the array by incrementing the TOP  
variable by 1


2.POP:
STEP 1:Create a pop(),  store the deleted value in a variable.
STEP 2: Decrement the TOP variable by 1.

3.DISPLAY:
STEP 1:Create a function display(), print the values by decrementing index 
value by 1 upto it becomes 0.


PROGRAM:
#include<iostream.h>
#include<conio.h>
#include<stdlib.h>
#define size 5
class STACK_CLASS
{
private:
struct stack
{
int s[size];
int top;
}
st;
public:
STACK_CLASS();
int stfull();
void push(int item);
int stempty();
int pop();
void display();
};
STACK_CLASS::STACK_CLASS()
{
st.top=-1;
for(int i=0;i<size;i++)
st.s[i]=0;
}
int STACK_CLASS::stfull()
{
if(st.top>=size-1)
return 1; 
else 
return 0; 
} 
void STACK_CLASS::push(int item) 
{ 
st.top++; 
st.s[st.top]=item; 
} 
int STACK_CLASS::stempty() 
{ 
if(st.top==-1) 
return 1; 
else 
return 0; 
} 
int STACK_CLASS::pop() 
{ 
int item; 
item=st.s[st.top]; 
st.top--; 
return(item); 
} 
void STACK_CLASS::display() 
{ 
int i; 
if(stempty()) 
cout<<"\n Stack is Empty!"; 
else 
{ 
for(i=st.top;i>=0;i--) cout<<"\n<<st.s[i]"; 
} 
} 
void main(void) 
{ 
int item,choice; 
char ans; 
STACK_CLASS obj; 
clrscr(); 
cout<<"\n\t\t implementation of Stack"; 
do 
{ 
cout<<"\n Main Menu"; 
cout<<"\n 1.Push\n 2.Pop\n 3.Display\n 4.exit"; 
cout<<"\n Enter your choice:"; 
cin>>choice; 
switch(choice) 
{ 
case 1: 
cout<<"\n Enter the item to be pushed"; 
cin>>item; 
if(obj.stfull()) 
cout<<"\n Stack is full"; 
else 
obj.push(item); 
break; 
case 2: 
if(obj.stempty()) 
cout<<"\n empty stack !underflow!!"; 
else 
{ 
item=obj.pop(); 
cout<<"\n the popped element is"<<item; 
} 
break; case 3: 
obj.display(); 
break; 
case 4: exit(0); 
} 
cout<<"\n Do u Want To Continue?"; 
ans=getch(); 
} 
while(ans=='Y'||ans=='y'); 
getch();} 

OUTPUT :  
Implementation Of Stack 
Main Menu 
1. Push 
2. Pop 
3. Display 
4. exit 
Enter Your Choice : 1 
Enter The item to be pushed 10 
You want To Continue?y Enter Your Choice : 1 
Enter The item to be pushed 20 
Do You want To Continue?y 
Enter Your Choice : 1 
Enter The item to be pushed 30 
Do You want To Continue?y 
Enter Your Choice : 2 
The popped element is 30 
Do You want To Continue?y 
Enter Your Choice : 3 
20 10 
Do You want To Continue?n