Create a vector with initial values using curly braces: vector<int> numbers = {10, 20, 30};. This creates a vector with three elements already inside. To create with a specific size: vector<int> scores(5); gives five elements, all zero.
Set a default value: vector<int> scores(5, 100); creates five elements, each 100. Choose the approach that fits. Empty vectors work when you'll add elements later. Sized vectors work when you know the count upfront.