Stack Program

//  Stack Program
//  Date : 08.04.19
#include<iostream>
#include<cstdlib>
#define max_size 20
using namespace std;

class stack_class{
    int stack_array[max_size];
    int top;
    void insert_stack();
    void delete_stack();
    void display();
public:
    stack_class() { top = 0; }
    void control_function();
};

void stack_class::display(){
    if(top == 0){
        cout << "The Stack is Underflow nothing to display.\n";
        return;
    }
    else{
        cout << "The element in the Stack are: \n";
        for(int i = top-1; i > -1; i--){
            cout << stack_array[i] << ' ';
        }
        cout << endl << endl;
    }
}

void stack_class::delete_stack(){
    if(top == 0){
        cout << "The Stack is Underflow.\n";
        return;
    }
    else{
        cout << "The element " << stack_array[--top]
             << " is deleted\n";
    }
}

void stack_class::insert_stack(){
    if(top == max_size){
        cout << "The Stack is Overflow.\n";
        return;
    }
    else{
        cout << "Enter Element to display: ";
        cin >> stack_array[top++];
    }
}

void stack_class::control_function(){
    while(1){
        cout << "* * * * * Welcome to Stack program * * * * *\n"
            << "Press 1 to Insert.\n"
            << "Press 2 to Delete.\n"
            << "Press 3 to Display Stack.\n"
            << "Press 4 to Exit.\n"
            << "\nEnter your choice: ";
        int choice; cin >> choice;
        system("cls");

        if(choice == 1) insert_stack();
        else if(choice == 2) delete_stack();
        else if(choice == 3) display();
        else if(choice == 4) break;
        else cout << "Wrong Choice.\n\n";
    }
}

int main(){
    stack_class ob1;
    ob1.control_function();

    return 0;
}