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https://www.geeksforgeeks.org/initialize-a-vector-in-cpp-different-ways/

Following are different ways to create and initialize a vector in C++ STL

Initializing by one by one pushing values :

#include <bits/stdc++.h>

using namespace std;

int main()

{

    vector<int> vect;

    vect.push_back(10);

    vect.push_back(20);

    vect.push_back(30);

    for (int x : vect)

        cout << x << " ";

    return 0;

}

Output:

10 20 30

Specifying size and initializing all values :

#include <bits/stdc++.h>

using namespace std;

int main()

{

    int n = 3;

    vector<int> vect(n, 10);

    for (int x : vect)

        cout << x << " ";

    return 0;

}

Output:

10 10 10

Initializing like arrays :

#include <bits/stdc++.h>

using namespace std;

int main()

{

    vector<int> vect{ 10, 20, 30 };

    for (int x : vect)

        cout << x << " ";

    return 0;

}

Output:

10 20 30

Initializing from array :

#include <bits/stdc++.h>

using namespace std;

int main()

{

    int arr[] = { 10, 20, 30 };

    int n = sizeof(arr) / sizeof(arr[0]);

    vector<int> vect(arr, arr + n);

    for (int x : vect)

        cout << x << " ";

    return 0;

}

Output:

10 20 30

Initializing from another vector :

#include <bits/stdc++.h>

using namespace std;

int main()

{

    vector<int> vect1{ 10, 20, 30 };

    vector<int> vect2(vect1.begin(), vect.end());

    for (int x : vect2)

        cout << x << " ";

    return 0;

}

Output:

10 20 30