C++ Stack Implementation Using Template And Exceptions

#include <iostream>
#include <stdexcept>
#include <cstdlib>
#include <string>
using namespace std;

template <class T>
class Stack
{
    private:
        T *stk;
        int size, tos, maxsize;
    public:
        Stack(int);
        ~Stack() {delete [] stk;} 
        T top() const;
        void pop();
        void push(T);
        template <class sT> friend ostream& operator<<(ostream &, const Stack<sT> &);   
        bool isempty() const {
            return (size == 0);
        }   
};

template <class T>
Stack<T>::Stack(int s)
{
    size = 0;
    maxsize = s;
    tos = -1;
    if (s <= 0) {
        throw out_of_range("stack(): size cant be zero or nagative.");
    }
    else {
        stk = new T[maxsize];
    }
}

template <class sT>
ostream& operator<<(ostream &out, const Stack<sT> &s)
{
    int i;
    cout << '[';
    for (i = 0; i < s.size; i++) {
        out << s.stk[i] << "," << ends;
    }
    cout << "\b\b";
    cout << ']';
    return out;
}

template <class T>
T Stack<T>::top() const 
{
    if (isempty()) {
        throw out_of_range("top() error: stack is empty.");
    }
    else {
        return stk[tos];
    }
}

template <class T>
void Stack<T>::push(T elem)
{
    if(size == maxsize) {
        throw out_of_range("push error: Stack is full.");
    }
    else {
        stk[++tos] = elem;
        ++size;
    }
}

template <class T>
void Stack<T>::pop()
{
    if(isempty()) {
        throw out_of_range("pop() error: Stack is full.");
    }
    else {
        size--;
        tos--;
    }
}


int main()
{
    try {
        cout << "<For Integers>" << endl;
        Stack<int> s(5);
        s.push(1);
        s.push(2);
        s.push(3);
        s.push(4);
        cout << "Stack:" << s << endl;
        
        cout << "\n<For Strings>" << endl;
        Stack<string> g(4);
        g.push("Superman");
        g.push("Batman");
        g.push("Flash");
        g.push("Spiderman");
        cout << "Stack:[";
        while(!g.isempty()) {
            cout << g.top() << "," << ends;
            g.pop();
        }
        cout << "\b\b]" << endl;
        
        cout << "\n<Exception>" << endl;
        Stack<int> j(0);
    }
    catch(exception &e) {
        cerr << e.what() << endl;
        return EXIT_FAILURE;
    }
    return EXIT_SUCCESS;
}

<For Integers>
Stack:[1, 2, 3, 4]
<For Strings>
Stack:[Spiderman, Flash, Batman, Superman]
<Exception>
stack(): size cant be zero or nagative.

--------------------------------
Process exited after 0.3268 seconds with return value 1
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