Strange output using for loop

[Musica]

I added(push) 4 items in a stack, right. Then, I wanted to remove all the items using pop function.

 cout<<"\nDisplay all elements of stack"<<endl;
	for(int i=0;i<trivial_stk.size();++i)
	trivial_stk.peek(i);	//outputs: "he" "hel" "hell" and "hello"
	
	cout<<trivial_stk.size()<<endl; //output: 4 

	cout<<"\nPop elements off stack four times"<<endl;
	trivial_stk.pop(); //output:"hello"
	trivial_stk.pop();// output:"hell"
	trivial_stk.pop();// output:"hel" 
	trivial_stk.pop(); //output: "he"

     cout<<trivial_stk.size()<<endl; //output: 0 

The above codes works fine

However, when I used for loop in implementing trivial_stk.pop();
It just goes until j=1 then loop stops.

cout<<trivial_stk.size()<<endl; //output: 4 

cout<<"\nPop elements off stack four times"<<endl;
	for(int j=0;j<trivial_stk.size();++j) 
	{trivial_stk.pop(); //outputs only "hello" and "hel"
}

cout<<trivial_stk.size()<<endl; //output: 2 

[Chervil]

There is double counting here:

    for(int j=0;j<trivial_stk.size();++j) 

j increases on each pass.
trivial_stk.size() decreases on each pass.

You could try either this:

    int limit = trivial_stk.size();
    for (int j=0; j<limit; ++j) 

or simply,

    while (trivial_stk.size())