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

In C++, a stack of vectors can be created using the Standard Template Library (STL). The stack is a container adapter that provides a Last-In-First-Out (LIFO) type of data structure, and a vector is a dynamic array that can grow and shrink in size. In this article, we will learn how to create a stack of vectors in C++.

Example

Input:
myVector1 = { 1, 4, 3, 2, 10}
myVector2 = {5, 1, 3, 4, 8}

Output:
myStack: [ { 1, 4, 3, 2, 10},
                    {5, 1, 3, 4, 8} ]

Stack of Vectors in C++

To create a std::stack of std::vector, we can define the type of stack as the std::vector by passing it as the template parameter. In this way, each element of the stack will be a vector.

Syntax to Declare a Stack of Vector

stack <vector <type>> myStack;

C++ Program to Create a Stack of Vectors

C++

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

int main()
{
    // Declaring a stack of vectors
    stack<vector<int> > myStack;

    // Creating some vectors
    vector<int> vec1 = { 1, 2, 3 };
    vector<int> vec2 = { 4, 5, 6 };
    vector<int> vec3 = { 7, 8, 9 };

    // Pushing vectors into the stack
    myStack.push(vec1);
    myStack.push(vec2);
    myStack.push(vec3);

    // printing the stack
    cout << "MyStack:" << endl;
    while (!myStack.empty()) {
        auto ele = myStack.top();
        cout << " {";
        for (auto i : ele) {
            cout << i << " ";
        }
        cout << "}" << endl;
        myStack.pop();
    }

    return 0;
}

Output

MyStack:
 {7 8 9 }
 {4 5 6 }
 {1 2 3 }

Time Complexity: O(N), where N is the number of vectors.
Auxiliary Space: O(N)