Instantiation of Templates - c++

Question

Please see the following code:
// templateClassTemplate.cpp
#include <iostream>
class Account{
public:
explicit Account(double amount=0.0): balance(amount){}
void deposit(double amount){
balance+= amount;
}
void withdraw(double amount){
balance-= amount;
}
double getBalance() const{
return balance;
}
private:
double balance;
};
template <typename T, int N>
class Array{
public:
Array()= default;
int getSize() const;
private:
T elem[N];
};
template <typename T, int N>
int Array<T,N>::getSize() const {
return N;
}
int main(){
std::cout << std::endl;
Array<double,10> doubleArray;
std::cout << "doubleArray.getSize(): " << doubleArray.getSize() << std::endl;
Array<Account,1000> accountArray;
std::cout << "accountArray.getSize(): " << accountArray.getSize() << std::endl;
std::cout << std::endl;
}
This code is taken from a learning course on template initialisation.
I have two questions:
How is the object Array<double,10> doubleArray initialized since it is using a default constructor that takes no arguments?
How is the object Array<Account,1000> accountArray initialized?

Answer 1

The template is instantiated by replacing the type T in the template with the type given as the first argument, and the integer N with the value of the second argument.
The same thing happens when instantiating the definition of getSize.
That is, Array<double,10> doubleArray; works exactly the same as
class DoubleArray10{
public:
DoubleArray10()= default;
int getSize() const;
private:
double elem[10];
};
int DoubleArray10::getSize() const { return 10; }
DoubleArray10 doubleArray;
and Array<Account,1000> accountArray; works exactly like
class AccountArray1000{
public:
AccountArray1000()= default;
int getSize() const;
private:
Account elem[1000];
};
int AccountArray1000::getSize() const { return 1000; }
AccountArray1000 accountArray;