First thing's first, you have some major issues with your pop method.

• You correctly replace head with the next node in the chain but you never delete the previous node, leading to a memory leak.
• The method returns before you set the head to null on the empty condition.
• Less sever but you're comparing to true and false, which is a redundancy very commonly found in beginner code.

This should be rectified like so:

    if(!this->isEmpty()) // !true = false, !false = true
    {
        T data = std::move(temp->head->data); // Move the data out of the node

        Node *temp = this->head_;
        this->head_ = this->head_->next_;
        this->size_ --;
        delete temp; // Delete the node so it doesn't leak

        if(this->isEmpty()) // == true comparison was redundant
            this->head_ = nullptr; // Use nullptr, not NULL

        return data;
    }
    else
    {
        throw std::out_of_range("The Stack Is Empty!");
    }

More about std::move.

More about not using == true.

More about new and delete

Advice 1: Const Correctness

This is probably less important than other answers but you should try to make your code const-correct.

isEmpty and getSize should be marked const.

This means you'll be able to use them from a const reference to an instance of TStack.

Advice 2: nullptr

If you're using a modern (C++11 onwards) compiler, user nullptr instead of the archaic NULL.

Extra suggestion:

Add a const T& peek() const method so you can examine the top of the stack without removing it. This isn't completely necessary but if I were one of the people using your stack object I'd expect the peek operation to be available.

First thing's first, you have some major issues with your pop method.

• You correctly replace head with the next node in the chain but you never delete the previous node, leading to a memory leak.
• The method returns before you set the head to null on the empty condition.
• Less sever but you're comparing to true and false, which is a redundancy very commonly found in beginner code.

This should be rectified like so:

    if(!this->isEmpty()) // !true = false, !false = true
    {
        T data = std::move(temp->head->data); // Move the data out of the node

        Node *temp = this->head_;
        this->head_ = this->head_->next_;
        this->size_ --;
        delete temp; // Delete the node so it doesn't leak

        if(this->isEmpty()) // == true comparison was redundant
            this->head_ = nullptr; // Use nullptr, not NULL

        return data;
    }
    else
    {
        throw std::out_of_range("The Stack Is Empty!");
    }

More about std::move.

More about not using == true.

More about new and delete

Advice 1: Const Correctness

This is probably less important than other answers but you should try to make your code const-correct.

isEmpty and getSize should be marked const.

This means you'll be able to use them from a const reference to an instance of TStack.

Advice 2: nullptr

If you're using a modern (C++11 onwards) compiler, user nullptr instead of the archaic NULL.

Extra suggestion:

Add a const T& peek() const method so you can examine the top of the stack without removing it. This isn't completely necessary but if I were one of the people using your stack object I'd expect the peek operation to be available.

I started writing some advice when I suddenly realised your code logic is actually horribly broken and I'm amazed nobody noticed.

In push you create a new node assign the node's next assign the new node to head

First thing's first, you have some major issues with your pop method.

• You correctly replace head with the next node in the chain but you never delete the previous node, leading to a memory leak.
• The method returns before you set the head to null on the empty condition.
• Less sever but you're comparing to true and false, which is a redundancy very commonly found in beginner code.

This should be rectified like so:

    if(!this->isEmpty()) // !true = false, !false = true
    {
        T data = std::move(temp->head->data); // Move the data out of the node

        Node *temp = this->head_;
        this->head_ = this->head_->next_;
        this->size_ --;
        delete temp; // Delete the node so it doesn't leak

        if(this->isEmpty()) // == true comparison was redundant
            this->head_ = nullptr; // Use nullptr, not NULL

        return data;
    }
    else
    {
        throw std::out_of_range("The Stack Is Empty!");
    }

More about std::move.

More about not using == true.

More about new and delete

Advice 1: Const Correctness

This is probably less important than other answers but you should try to make your code const-correct.

isEmpty and getSize should be marked const.

This means you'll be able to use them from a const reference to an instance of TStack.

Advice 2: nullptr

If you're using a modern (C++11 onwards) compiler, user nullptr instead of the archaic NULL.

Extra suggestion:

Add a const T& peek() const method so you can examine the top of the stack without removing it. This isn't completely necessary but if I were one of the people using your stack object I'd expect the peek operation to be available.