Programming

C++ | Vector Initialization

Table Of Contents
  1. Initialize vector from array
  2. Initialize from another vector
  3. Initialize in constructor
  4. Initialize with default values
  5. Populate empty vector

Initialize vector from array

#include <iostream>
#include <vector>
using namespace std;

int main() {
  int arr[10] = {9, 9, 7, 9, 7, 8, 8, 7, 8, 0};
  vector<int> vec(arr, arr + 10);
  for (int item : vec)
    cout << item << " ";

  return 0;
}

Initialize from another vector

#include <iostream>
#include <vector>
using namespace std;

int main() {
  vector<int> vec1{9, 9, 7, 9, 7, 8, 8, 7, 8, 0};
  vector<int> vec2(vec1.begin(), vec1.end());

  for (int item : vec1)
    cout << item << " ";

  return 0;
}

Initialize in constructor

#include <iostream>
#include <vector>
using namespace std;

int main() {
  vector<int> vec{9, 9, 7, 9, 7, 8, 8, 7, 8, 0};

  for (int item : vec)
    cout << item << " ";

  return 0;
}

Initialize with default values

#include <iostream>
#include <vector>
using namespace std;

int main() {
  int n = 10;  // size of vector

  vector<int> vec(n, 99);

  for (int item : vec)
    cout << item << " ";

  return 0;
}

Populate empty vector

#include <iostream>
#include <vector>
using namespace std;

int main() {
  vector<int> vec;

  for (size_t i = 0; i < 10; i++)
    vec.push_back(10 + i);

  for (int item : vec)
    cout << item << " ";

  return 0;
}

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