C++ Initializing a Vector in STL (Part 2) Program

Hello Everyone!

In this tutorial, we will learn about the various ways of initializing a Vector (Part 2), in the C++ programming language.

What are Vectors?

Vectors are the same as dynamic arrays with the ability to resize itself automatically when an element is inserted or deleted. This makes them more advantageous over the ordinary Arrays which are of fixed size and are static in nature.

To learn more about Vectors in CPP, we will recommend you to visit C++ STL Vector

For better understanding, refer to the well-commented C++ code given below.

Code:

#include <iostream>
#include <bits/stdc++.h>

using namespace std;

int main()
{
    cout << "\n\nWelcome to Studytonight :-)\n\n\n";
    cout << " =====  Program to demonstrate the various ways of Initializing a Vector (Part 2), in CPP  ===== \n\n";

    cout << "Method 1: Initialize a Vector like an Array\n\n";

    //create and initialize a vector
    vector<int> v{1, 2, 3, 4};

    //prining the vector
    cout << "The elements of the first vector are: ";

    for (int i : v)
    {
        cout << i << " ";
    }

    cout << "\n\n\nMethod 2: Initializing a Vector from an Array\n\n";

    //creating and initializing an array
    int a[] = {11, 22, 33};

    //calculating number of elements in an array
    int n = sizeof(a) / sizeof(a[0]);

    //creating and initializing a vector with the array elements
    vector<int> v1(a, a + n);

    //prining the vector
    cout << "The elements of the second vector are: ";
    for (int i : v1)
    {
        cout << i << " ";
    }

    cout << "\n\n\nMethod 3: Initializing a Vector from another Vector\n\n";

    //creating and initializing the source vector
    vector<int> a1 = {10, 22, 33};

    //creating and initializing a second vector with the elements of the first vector
    vector<int> b(a1.begin(), a1.end());

    //prining the vector
    cout << "The elements of the third vector are: ";
    for (int i : b)
    {
        cout << i << " ";
    }

    cout << "\n\n\n";

    return 0;
}

Output:

We hope that this post helped you develop a better understanding of the concept of Vector and its implementation in CPP. For any query, feel free to reach out to us via the comments section down below.

Keep Learning : )