Tmplate Class w/ User-defined class as argument

[Musica]

I have no idea how can I pass the class I created (Trivial class) to the template class (Stack class).
Below passing pre-defined type such as int, double, char works fine.

some codes i wrote in main

   Stack <int> int_stk; //this works fine
  Stack <char> char_stk; //this works fine
  int_stk.push(1);
int_stk.push(2);
int_stk.push(3);
int_stk.size();  // outputs 3
int_stk.pop();   // outputs 3
int_stk.pop();   // outputs 2
int_stk.pop();   // outputs 1
int_stk.pop();   // outputs "The stack is empty."
int_stk.size();  // outputs 0

//My problem is below

  Stack <Trivial> trivial_stk; //gives error
  trivial_stk.push("Hello"); 
  trivial_stk.push("Hi");
  trivial_stk.push("GoodBye");

Stack class header file (I didnt include the cpp file)

 template< class T >
class Stack
{
 
public:
 Stack( int = 10 ); // default constructor (stack maxSize 10)
 ~Stack();
 void push( const T& ); 
 void pop(); 
 bool isEmpty() const; 
 bool isFull() const;
 void size() const;
 void peek(const int&) const;

 private:
 int maxSize; // number of elements in the stack
 int top; // location of the top element
 T *stackPtr; // pointer to the stack
};

Trivial class

 #include <iostream>
#include <string>


using namespace std;


class Trivial
{
 
public:
 Trivial(const string &);
 ~Trivial();
 void setString(const string &);
 string getString() const;
 void printString() const;

 
 private:
 string stringName;
};

// constructor

Trivial::Trivial(const string &n) {
 
	stringName=n;
}

void Trivial::setString(const string &n)
{
	stringName=n;
}
 string Trivial::getString() const
 {
  return stringName;
 
 }
 void Trivial::printString() const
 {
  cout<<getString()<<endl;

 }

 // destructor
Trivial::~Trivial() {

}

[Moschops]

Stack <Trivial> trivial_stk; //gives error
What error does it give?

[Musica]

The errors are something like:

error C2512: 'Trivial' : no appropriate default constructor available ...
while compiling class template member function 'Stack<T>::Stack(int)'
1> with
1> [
1> T=Trivial
1> ]
1> c:\users\dexter\desktop\c++2\as4\driver.cpp(93) : see reference to function template instantiation 'Stack<T>::Stack(int)' being compiled
1> with
1> [
1> T=Trivial
1> ]
1> c:\users\dexter\desktop\c++2\as4\driver.cpp(93) : see reference to class template instantiation 'Stack<T>' being compiled
1> with
1> [
1> T=Trivial
1> ]
............

error C2679: binary '<<' : no operator found which takes a right-hand operand of type
'Trivial' (or there is no acceptable conversion)

could be 'std::basic_ostream<_Elem,_Traits> &std::operator <<<char,std::char_traits<char>>(std::basic_ostream<_Elem,_Traits> &,const char *)'
1> with
1> [
1> _Elem=char,
1> _Traits=std::char_traits<char>
1> ]

..................

[Moschops]

Somewhere, you're trying to create objects of type Trivial using this default constructor: Trivial::Trivial() which does not exist.

Show us the Stack constructor.

[Musica]

I did something like below

//header
Trivial(const string=NULL);


//implementation
Trivial::Trivial(const string n): stringName(n) {
 

}

The first error was gone. Thanks!!

But I still have another error.

[Musica]

Based on what I read, I think I need to that I need to overload << . I am not familiar with operator overloading.

I tried writing codes below in Trivial class

//header
friend ostream &operator<<( ostream &, const Trivial & );

//implementation
ostream &operator<<( ostream &output, const Trivial &r )
{
/*something */
return output;
}

Compiliation was successful. However, after console was up,
it gave me a message like : Debug Assertion Failed! ... Line:1154 .... Expression: invalid null pointer...

[Musica]

I guess I need to put some codes of the Stack class implementation

// constructor
template< class T >
Stack< T >::Stack( int s = 10) {
 maxSize = s;
 top = -1; // stack initially empty
 stackPtr = new T[ maxSize ]; // allocate memory for elements
}
// destructor
template< class T >
Stack< T >::~Stack() {
 delete [] stackPtr;
}
// push element onto stack;
template< class T >
void Stack< T >::push( const T &value ) {
 if ( !isFull() )
 stackPtr[ ++top ] = value;
 else
cout <<"Stack is full" << endl;
} 

// pop element off stack;
template< class T >
void Stack< T >::pop() {
 if ( !isEmpty() ) 
  cout<<stackPtr[ top--] << endl; // remove item from Stack
 else
 cout<<"Stack is empty" << endl;
}

// check if stack is empty
template< class T >
bool Stack< T >::isEmpty() const {
 return top == -1;
}