STACK:
While writing your applications you need to use the stack. Stack is basically a LIFO (Last In First Out). It is opposite to queue which is FIFO(First In First Out). Stack is very easy to program if it has defined capacity. But if you don’t know the capacity or size you have to create it dynamically in c++. Which is quite trickier than normal array stack in c++. Its basically made using linked list . Here is the basic structure of stack in c++:
struct node{
int data;
node *link;
};
Insertion In Stack:
The insertion in stack is very easy. Create a new node and attach it to the start of list. Here is how you can code to insert in stack in c++
void insert()
{
int b;
cout<<”Enter the data…”<<endl;
cin>>b;
node *temp=new node();
temp->data=b;
temp->link=NULL;
if(top==NULL)
top=temp;
else
{
temp->link=top;
top=temp;
}
}
Display Entries in Stack:
To display the entries in stack, its very easy. You can do like this.
void display()
{
system(“CLS”);
node *ptr=top;
while(ptr!=NULL)
{
cout<<ptr->data<<endl;
ptr=ptr->link;
}
system(“pause”);
}
Deleting Last Data in Stack:
In Stack you can delete the last data as follow:
void remove()
{
node *temp=top;
top=top->link;
delete temp;
}
Complete Code:
#include<iostream>
using namespace std;
struct node
{
int data;
node *link;
};
node *top=NULL;
void insert();
void remove();
void display();
int main ()
{
int a;
while (1)
{
system(“CLS”);
cout<<”Press 1 to insert, 2 to delete, 3 to display the stack n 4 to exit”<<endl;
cin>>a;
switch(a)
{
case 1:
insert();
break;
case 2:
remove();
break;
case 3:
display();
break;
case 4:
exit(0);
}
}
system(“pause”);
return(0);
}
void insert()
{
int b;
cout<<”Enter the data…”<<endl;
cin>>b;
node *temp=new node();
temp->data=b;
temp->link=NULL;
if(top==NULL)
top=temp;
else
{
temp->link=top;
top=temp;
}
}
void remove()
{
node *temp=top;
top=top->link;
delete temp;
}
void display()
{
system(“CLS”);
node *ptr=top;
while(ptr!=NULL)
{
cout<<ptr->data<<endl;
ptr=ptr->link;
}
system(“pause”);
}
Output:
