declare c++ vector code example

Example 1: how to create a vector in c++

// CPP program to create an empty vector 
// and push values one by one. 
#include <vector>

using namespace std;
int main() 
{ 
    // Create an empty vector 
    vector<int> vect;  
    //add/push an integer to the end of the vector
    vect.push_back(10); 
	//to traverse and print the vector from start to finish
    for (int x : vect) 
        cout << x << " ";

    return 0; 
}

Example 2: how to create a vector in c++

// First include the vector library:
#include <vector>

// The syntax to create a vector looks like this:
std::vector<type> name;

// We can create & initialize "lol" vector with specific values:
std::vector<double> lol = {66.666, -420.69};

// it would look like this: 66.666 | -420.69

Example 3: declare vectors c++

vector<int> vec;
//Creates an empty (size 0) vector
 

vector<int> vec(4);
//Creates a vector with 4 elements.

/*Each element is initialised to zero.
If this were a vector of strings, each
string would be empty. */

vector<int> vec(4, 42);

/*Creates a vector with 4 elements.
Each element is initialised to 42. */


vector<int> vec(4, 42);
vector<int> vec2(vec);

/*The second line creates a new vector, copying each element from the
vec into vec2. */