In C++ one can create an array of predefined size, such as 20, with int myarray[20]. However, the online documentation on vectors doesn't show an alike way of initialising vectors: Instead, a vector should be initialised with, for example, std::vector<int> myvector (4, 100);. This gives a vector of size 4 with all elements being the value 100.
How can a vector be initialised with only a predefined size and no predefined value, like with arrays?
With the constructor:
// create a vector with 20 integer elements
std::vector<int> arr(20);
for(int x = 0; x < 20; ++x)
arr[x] = x;
Source: Stackoverflow.com