String Class

[u8sand]

Hello everyone, i have not posted here in a while. But i have a question about a string class I'm creating. Every time i make a string class this always happens, and i cannot figure out why. Maybe its something i didn't include or something i have to add. But i hope someone here will be able to answer my question.

class StRiNg
	{
	public:
		StRiNg()
		{
			sTrLeN = 0;
			sTr = new char[1];
			sTr[0] = '\0';
		}
		StRiNg(char* s)
		{
			sTrLeN = (int)strlen(s);
			sTr = new char[(sTrLeN+1)];
			for(int i = 0; i < sTrLeN; i++)
				sTr[i] = s[i];
			sTr[sTrLeN] = '\0';
		}
		~StRiNg()
		{
			delete sTr;
			sTrLeN = 0;
		}

		StRiNg operator=(char* s)
		{
			try
			{
				delete sTr;
				sTrLeN = (int)strlen(s);
				sTr = new char[(sTrLeN+1)];
				for(int i = 0; i < sTrLeN; i++)
					sTr[i] = s[i];
				sTr[sTrLeN] = '\0';
			}
			catch(...)
			{
				return *this;
			}
			return *this;
		}

		bool operator==(char* s)
		{
			try
			{
				if((int)strlen(s) != sTrLeN)
					throw 0;
				bool same = true;
				for(int i = 0; i < sTrLeN && same; i++)
				{
					if(sTr[i] != s[i])
						same = false;
				}
				if(!same)
					throw 0;
			}
			catch(...)
			{
				return false;
			}
			return true;
		}
		bool operator!=(char* s)
		{
			if(*this == s)
				return false;
			return true;
		}

		char operator[](int num)
		{
			try
			{
				if(num < 0 || num > sTrLeN)
					throw 0;
				return sTr[num];
			}
			catch(...)
			{
				return '\0';
			}
			return '\0';
		}
		char* GetString() { return sTr; }
		int GetLength() { return sTrLeN; }
	protected:
		char* sTr;
		int sTrLeN;
	};

That is the base of my class, of course i will add other functions.. but here is my problem:

int main()
{
    StRiNg s1 = "Hello";
    StRiNg s2 = "How are you?";
    cout << s1.GetString() << endl; // works fine
    cout << s2.GetString() << endl; // works fine
    // Here is where the problem starts:
    s1 = s2.GetString();
    cout << s1.GetString() << endl; // should be How are you but it is far from that, i get random characters...
    return 0;
}

I would have added an = operator for other strings but if it doesn't even work this way, i don't know whats wrong.
And last: if anyone knows, is there a way i could do like cout << s1 << endl; without having to put the .GetString() like make a default return value for the StRiNg or overload cout to allow that?

Thanks a lot for any help anyone might give me. (even if i don't get any XD)

[Lerner]

Try outputting the value of sTr immediately before leaving the try block in the assignment operator.

[u8sand]

Nope still same error. Thanks anyway.

[ArkM]

1. Wrong assignment operator (default member by member assignment can't work with such objects - think why).
2. No correct copy constructor (default copy constructor can't copy such objects). That's why your program crashed.
3. Some other defects ;)

StRiNg::StRiNg(const char* s) // const !
{
    if (s == 0) s = ""; // you forgot to test nullptr
    // now make as usually
}
StRiNg::StRiNg(const StRiNg& s) // copy constructor
{
    // make new dynamic copy of s
}
StRiNg& StRiNg::operator=(const StRiNg& s)
{
    if (this != &s) {
       delete [] sTr;
       // now make new dynamic copy of s   
    }
    return *this;
}
// GetString, bye forever:
operator const char*() const { return sTr; }

No needs in operator=(const char*) now: you have const char* to StRiNg constructor.

std::ostream& operator <<(std::ostream& os, const StRiNg& s)
{
    return os << sTr;
}

Now you can print your StRiNgS aS uSuAlLy.

[u8sand]

Thanks a lot, i will try all these out.
IF anything i will post back here.

and if anyone else finds something please also post it.

[u8sand]

Well i did all the stuff you told me, still have a few problems tho -.-.
First of all, i still get crazy characters after i copy...
Second of all: i get an error when i try to add:

std::ostream& operator <<(std::ostream& os, const StRiNg& s)
      {
      return os << sTr;
      }

But that is fine because

operator const char*() const { return sTr; }

does the job anyway.

but another prob is that when i pass the parameter as a string (const StRiNg& s)
i cannot do s.GetLength(); but that may be because of the const char* operator.

So overall i'm good, only prob is i'm still getting crazy characters.

[mvmalderen]

Why are you using such weird naming like: "StRiNg"
??

Why don't you just call it 'mystring', 'mystrlen', etc. or something ?
It will be much easier to type ...
Unless you don't care by everytime type an UPPERCASE character, and after it a lowercase character ...

It's your choice ...

[u8sand]

Well i use StRiNg so i don't get confused with any other string or String class already created... I made a file class and called it FiLe.
plus i like the look to StRiNg XD but that doesn't have much to do w/ this. I'm marking this as solved because i found my answer already. Thanks for all your help.

[mvmalderen]

Well i use StRiNg so i don't get confused with any other string or String class already created... I made a file class and called it FiLe.
plus i like the look to StRiNg XD but that doesn't have much to do w/ this. I'm marking this as solved because i found my answer already. Thanks for all your help.

OK, I understand your way to do it, as I said it's only a matter of choice ...