#include <iostream>
#include <cstdlib>   //for malloc, size_t, exit, EXIT_FAILURE
#include <cstring>   //for strcpy, strlen
#include "mystring.h"
using namespace std;

mystring::mystring(const mystring& another)   //the copy constructor
	: n(another.n), p(static_cast<char *>(malloc(n + 1)))
{
	if (p == 0) {
		cerr << "couldn't allocate " << n + 1 << " bytes\n";
		exit(EXIT_FAILURE);
	}

	strcpy(p, another.p);
}

mystring::mystring(const char *s)
	: n(strlen(s)), p(static_cast<char *>(malloc(n + 1)))
{
	if (p == 0) {
		cerr << "couldn't allocate " << n + 1 << " bytes\n";
		exit(EXIT_FAILURE);
	}

	strcpy(p, s);
}

mystring& mystring::operator=(const mystring& another)
{
	if (&another != this) {
		free(p);
		n = another.n;
		p = static_cast<char *>(malloc(n + 1));

		if (p == 0) {
			cerr << "couldn't allocate " << n + 1 << " bytes\n";
			exit(EXIT_FAILURE);
		}

		strcpy(p, another.p);
	}

	return *this;
}

mystring& mystring::operator=(const char *s)
{
	free(p);
	n = strlen(s);
	p = static_cast<char *>(malloc(n + 1));

	if (p == 0) {
		cerr << "couldn't allocate " << n + 1 << " bytes\n";
		exit(EXIT_FAILURE);
	}

	strcpy(p, s);
	return *this;
}

char& mystring::operator[](size_t i)
{
	if (i > n) {
		cerr << "Subscript " << i << " must be in range 0 to " << n
			<< " inclusive.\n";
		exit(EXIT_FAILURE);
	}

	return p[i];
}

const char& mystring::operator[](size_t i) const
{
	if (i > n) {
		cerr << "Subscript " << i << " must be in range 0 to " << n
			<< " inclusive.\n";
		exit(EXIT_FAILURE);
	}

	return p[i];
}