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vector::vector

Constructs a vector of a specific size or with elements of a specific value or with a specific allocator or as a copy of all or part of some other vector. Elements are stored in a contiguous memory block, and memory allocations are managed either by the default allocator or by a custom allocator that you supply.

vector( ); 
explicit vector(
    const Allocator& Al
);
explicit vector(
    size_type Count
);
vector(
    size_type Count,
    const Type& Val
);
vector(
    size_type Count,
    const Type& Val,
    const Allocator& Al
);
vector(
    const vector& Right
); 
vector(
    vector&& Right
);
vector(
    initializer_list<Type> IList,
    const _Allocator& Al
);
template<class InputIterator>
    vector(
        InputIterator First,
        InputIterator Last
    );
template<class InputIterator>
    vector(
        InputIterator First,
        InputIterator Last,
        const Allocator& Al
    );

Parameter

Description

Al

The allocator class to use with this object. get_allocator returns the allocator class for the object.

Count

The number of elements in the constructed vector.

Val

The value of the elements in the constructed vector.

Right

The vector of which the constructed vector is to be a copy.

First

Position of the first element in the range of elements to be copied.

Last

Position of the first element beyond the range of elements to be copied.

IList

The initializer_list containing the elements to copy.

All constructors store an allocator object (Al) and initialize the vector.

The first two constructors specify an empty initial vector. The second explicitly specifies the allocator type (Al) to be used.

The third constructor specifies a repetition of a specified number (Count) of elements of the default value for class Type.

The fourth and fifth constructors specify a repetition of (Count) elements of value Val.

The sixth constructor specifies a copy of the vector Right.

The seventh constructor moves the vector Right.

The eighth constructor uses an initializer_list to specify the elements.

The ninth and tenth constructors copy the range [First, Last) of a vector.

// vector_ctor.cpp
// compile with: /EHsc
#include <vector>
#include <iostream>

int main()
{
    using namespace std;
    vector <int>::iterator v1_Iter, v2_Iter, v3_Iter, v4_Iter, v5_Iter, v6_Iter;

    // Create an empty vector v0
    vector <int> v0;

    // Create a vector v1 with 3 elements of default value 0
    vector <int> v1(3);

    // Create a vector v2 with 5 elements of value 2
    vector <int> v2(5, 2);

    // Create a vector v3 with 3 elements of value 1 and with the allocator 
    // of vector v2
    vector <int> v3(3, 1, v2.get_allocator());

    // Create a copy, vector v4, of vector v2
    vector <int> v4(v2);

    // Create a new temporary vector for demonstrating copying ranges
    vector <int> v5(5);
    for (auto i : v5) {
        v5[i] = i;
    }

    // Create a vector v6 by copying the range v5[_First, _Last)
    vector <int> v6(v5.begin() + 1, v5.begin() + 3);

    cout << "v1 =";
    for (auto& v : v1){
        cout << " " << v;
    }
    cout << endl;

    cout << "v2 =";
    for (auto& v : v2){
        cout << " " << v;
    }
    cout << endl;

    cout << "v3 =";
    for (auto& v : v3){
        cout << " " << v;
    }
    cout << endl;
    cout << "v4 =";
    for (auto& v : v4){
        cout << " " << v;
    }
    cout << endl;

    cout << "v5 =";
    for (auto& v : v5){
        cout << " " << v;
    }
    cout << endl;

    cout << "v6 =";
    for (auto& v : v6){
        cout << " " << v;
    }
    cout << endl;

    // Move vector v2 to vector v7
    vector <int> v7(move(v2));
    vector <int>::iterator v7_Iter;

    cout << "v7 =";
    for (auto& v : v7){
        cout << " " << v;
    }
    cout << endl;

    vector<int> v8{ { 1, 2, 3, 4 } };
    for (auto& v : v8){
        cout << " " << v ;
    }
    cout << endl;
}
v1 = 0 0 0
v2 = 2 2 2 2 2
v3 = 1 1 1
v4 = 2 2 2 2 2
v5 = 0 1 2 3 4
v6 = 1 2
v7 = 2 2 2 2 2
1 2 3 4

Header: <vector>

Namespace: std

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