Stack In C++

Stack: 

Stack is a type of a linear data structure which follows a particular order to store data for specific use. Stack follows LIFO(Last In First Out) or FILO(First In Last Out).

Real Life Examples of Stack:

1.Stack of plates:




In the above mention picture there is a stack of plates like the computer stack it follows LIFO or FILO like if I want to take a plate then I can take only upper plate this same concept follows in stack we can just access top element of a stack.

Operations on stack:

1.PUSH():

    push operation used to enter the element at the top of stack.

2.pop():

    pop operation used to remove the top element form the stack and it return that element.

3.IsFull():

    IsFull operation used to check the stack is full or not .If stack is full then this condition known as the overflow.

4.IsEmpty():

    IsEmpty function used to check is stack is empty or not. If stack is empty then this condition known as the underflow.

5.peek():

    Peek function is used for access element form stack.

6.change():

    change function used for change the element at specific position in the stack.

Implementation of stack in c++ using array:


#include<iostream>
#include<string>
using namespace std;
class stack{
    private:
        int top;
        int arr[5];
    public:
        stack(){
            top=-1;
            for(int i=0;i<5;i++){
                arr[i]=0;
            }
        }


        bool IsEmpty(){
            if(top==-1)
                return true;
            else
                return false;
        }


        bool IsFull(){
            if(top==4)
                return true;
            else
                return false;
        }


        void push(int val){
            if(IsFull()){
                cout<<"can't Push, stack overflow"<<endl;
            }
            else{
                top++;
                arr[top]=val;
            }
        }


        int pop(){
            if(IsEmpty()){
                cout<<"stack underflow"<<endl;
                return 0;
            }
            else{
                int popval=arr[top];
                arr[top]=0;
                top--;
                return popval; 

            }

        }


        int count(){
            return top+1;
        }


        int peek(int pos){
            if(IsEmpty()){
                cout<<"stack underflow"<<endl;
                return 0;
            }
            else{
                return arr[pos];
            }
        }




        void change(int pos, int val){
            arr[pos]=val;
            cout<<"value has been changed"<<endl;

        }



        void display(){
            cout<<"stack is: "<<endl;
            for(int i=4;i>-1;i--){
                cout<<arr[i];
            }
        }

};


int main(){
    stack s1;
    int option, position , value;
    do{
        cout<<"0.exit"<<endl;
        cout<<"1.push"<<endl;
        cout<<"2.pop"<<endl;
        cout<<"3.IsEmpty"<<endl;
        cout<<"4.IsFull"<<endl;
        cout<<"5.peek"<<endl;
        cout<<"6.change"<<endl;
        cout<<"7.display"<<endl;
        cout<<"8.clear screen"<<endl;
        cin>>option;
        switch(option){

            case 1:
                cout<<"enter value for puch";
                cin>>value;
                s1.push(value);
                break;
            case 2:
                cout<<"pop function is called"<<s1.pop();
                break;
            case 3:
                if(s1.IsEmpty()){
                    cout<<"stack is Empty";
                }
                else{
                    cout<<"not Empty";
                }
                break;
            case 4:
                if(s1.IsFull())  {
                    cout<<"stack is full";
                }         
                else{
                    cout<<"stack is not empty you can push values";
                }
                break;
            case 5:
                cout<<"Enter the position";
                cin>>position;
                cout<<"value at given position: "<<s1.peek(position);
                break;
            case 7:
                s1.display();
                break;
            case 8:
                system("cls");
                break;
            default:
                cout<<" choose a correct option";


        }

    }
    while (option!=0);

    return 0;
}