How to Create a Stack of Arrays in C++?

In C++, the std::stack is a container that follows the LIFO (Last In, First Out) rule, whereas std::array is a sequence container that stores elements in contiguous memory. In this article, we will learn how to create a stack of an array in C++.

Example:

Input: 
arr1 = {1, 2, 3};
arr2 = {4, 5, 6};
arr3 = {7, 8, 9};
Output:
Stack of Array: [ {1, 2, 3},
                 {4, 5, 6},
                 {7, 8, 9} ]

Stack of Array in C++

To create a stack of arrays in C++, we can use the std::array container provided by the STL library. The std::array is a container that encapsulates fixed-size arrays. We can then create a stack of these arrays.

Syntax to Create Stack of Array in C++

stack<array<datatype, size>> stack_name;

Here,

• datatype denotes the type of data you want to store in the array.
• size denotes the size of each array present in the stack.
• stack_name is the name of the stack of array.

Note: The stack cannot be created with C-Style arrays as the type of the stack elements should be copy constructible and assignable.

C++ Program to Create a Stack of Arrays

The below program demonstrates how we can create a stack with an array in C++ STL.

// C++ Program to illustrate how to create a stack of arrays
#include <array>
#include <iostream>
#include <stack>
using namespace std;

int main()
{
    // Define the type of array
    typedef array<int, 3> ArrayType;

    // Initialize two arrays
    ArrayType array1 = { 1, 2, 3 };
    ArrayType array2 = { 4, 5, 6 };

    // Create a stack of arrays
    stack<ArrayType> myStack;
    myStack.push(array1);
    myStack.push(array2);

    // Print the stack of arrays
    while (!myStack.empty()) {
        ArrayType& topArray = myStack.top();
        for (int i : topArray) {
            cout << i << " ";
        }
        cout << endl;
        myStack.pop();
    }

    return 0;
}

4 5 6 
1 2 3 

Time Complexity: O(N), where N is the number of array.
Auxiliary Space: O(N * M), where M is the size of each array