//tstackx.cpp
//test driver for class Stack implemented using array
//exception handling is used to deal with error conditions

#include <iostream.h>
#include <stdlib.h>
#include "stackx.h"


void test_and_catch (int);


main ()	{
	int n = 8;

	//try block - where an exeption can be caught
	try {
		test_and_catch(n);
	}

	//catch block - to process an rxception
	catch(char *msg) {
		cerr<<"ERROR: "<<msg<<" caught in 'main'\n"
		    <<"Program terminated\n";
		exit(1);
	}

	return 0;
}


void test_and_catch(int sz) {

	//try block - where an exception can be caught
	try {
		cout<<"\n\t\tTest for exception handling in C++\n\n";

		Stack s(sz);
		if (!s.isempty())
			throw '1';    //stack should be empty

		for (int i = 1; i < 6; i++)
			s.push(i);

		if (s.isempty())
			throw '2';    //stack should nod be empty

		cout<<"Stack:\n";
		s.print();
		cout<<endl;

		cout<<"Adding more elements...\n\n";
		for (i = 10; i < 20; i++)
			s.push(i);
		cout<<"Stack now:\n";
		s.print();
		cout<<endl;


		cout<<"Now removing all elements from stack:\n";
		while(!s.isempty()) {
			i = s.pop();
			cout<<i<<" removed\n";
		}

		cout<<"Removing more elements\n\n";
		i = s.pop();

		cout<<"This sentence will never go to the output\n";

	}

	//catch blocks - to process exceptions caught in the try block
	catch (int n) {
		cerr<<"Warning: stack overflow\n"
		    <<"Current size "<<n<<" is too small\n"
		    <<"Resizing stack, ";
		sz = sz*2;
		cerr<<"new size: "<<sz<<endl
		    <<"Starting all over...\n";
		test_and_catch(sz);
	}

	catch (char *msg) {
		cerr<<"ERROR: "<<msg<<" caught in function 'test_and_catch'\n"
		    <<"BUT:   program continues\n"
		    <<"Rethrowing an exception\n\n";
		throw;   //exception can be rethrown and passed to the enclosing  
	                 //try block (in 'main')
	}

	catch (char ch) {
		if (ch=='1')
			cerr<<"Class Stack internal error("<<ch<<"). Stack should be empty.\n";
		else if (ch=='2')
			cerr<<"Class Stack internal error("<<ch<<"). Stack should not be empty.\n";
	}
}