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 :
// CPP program to create an empty vector // and one by one push values. #include <bits/stdc++.h> using namespace std; int main() { // Create an empty vector vector< int > vect; vect.push_back(10); vect.push_back(20); vect.push_back(30); for ( int x : vect) cout << x << " " ; return 0; } |
10 20 30
Specifying size and initializing all values :
// CPP program to create an empty vector // and one by one push values. #include <bits/stdc++.h> using namespace std; int main() { int n = 3; // Create a vector of size n with // all values as 10. vector< int > vect(n, 10); for ( int x : vect) cout << x << " " ; return 0; } |
Output:
10 10 10
Initializing like arrays :
// CPP program to initialize a vector like // array. #include <bits/stdc++.h> using namespace std; int main() { vector< int > vect{ 10, 20, 30 }; for ( int x : vect) cout << x << " " ; return 0; } |
10 20 30
Initializing from array :
// CPP program to initialize a vector 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; } |
10 20 30
Initializing from another vector :
// CPP program to initialize a vector 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; } |
10 20 30