Please review my code and help me to improve it. I have written this code using template. Can I use more C++11? Is using top in this code is necessary?
#include <iostream>
template<class T>
class Stack{
struct Node{
T data;
Node *next;
Node(T val):data(val),next(nullptr) {}
};
Node *head;
int top;
public:
Stack(){
top=-1;
head=nullptr;
}
~Stack();
bool stack_empty();
void push(T);
T pop();
void display(std::ostream& out = std::cout) const
{
Node *node=head;
while(node!=nullptr){
out<<node->data<<" ";
node=node->next;
}
}
};
template<class T>
bool Stack<T>::stack_empty(){
if(top==-1)
return true;
else
return false;
}
template<class T>
void Stack<T>::push(T val){
if(top>=-1){
top++;
Node *node=new Node(val);
Node *tmp=head;
if(tmp==nullptr) head=node;
else{
while(tmp->next!=nullptr)
tmp=tmp->next;
tmp->next=node;
}
}
else
std::cout<<"Overflow"<<std::endl;
}
template<class T>
T Stack<T>::pop(){
if(stack_empty()==true)
std::cout<<"Underflow"<<std::endl;
else{
top--;
Node *node=head;
while(node->next!=nullptr){
node=node->next;
}
return node->data;
}
}
template<class U>
std::ostream & operator <<(std::ostream& os, const Stack<U>& s){
s.display(os);
return os;
}
template<class T>
Stack<T>::~Stack(){
Node *tmp=nullptr;
while(head){
tmp=head;
head=head->next;
delete tmp;
}
head=nullptr;
}
int main()
{
Stack<int> stack1;
stack1.push(3);
stack1.push(4);
stack1.push(11);
stack1.push(30);
std::cout<<stack1<<std::endl;
std::cout<<stack1.pop()<<std::endl;
return 0;
}
