different ways to initialize vector c++ code example

Example 1: how to initialize vector in c++ with all elements 0

vector<int> arr(10,0);

Example 2: c++ initialize a vector

#include <bits/stdc++.h> 
#include <vector> 
using namespace std; 
  
int main() 
{ 
// This vector initializes with the values: 10, 20, and 30
  vector<int> vect{ 10, 20, 30 }; 

    return 0; 
}

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. */

Example 4: how to initialize vector

vector<int> vect{ 10, 20, 30 };

Example 5: how to initialize a vector in c++

std::vector<type> name;