strcmp - troubles compiling/running

[thejmfc]

Hello all. I'm trying to teach myself c++ in my spare time. To assist in that, I'm writing a basic program, just for learning purposes. It asks for several words, and uses them in a sentence. I've got that working. Now I'm going a step further and asking the sex of a previously inputted Name. The reply must be either Male or Female, if not, I want it to ask again for a correct reply. This would run as a continual loop until a correct answer is given. Easy enough, you would think.

The answer I've found in my searching looks like the following:

	string name; 		

	cout<<"Enter a name: \n";
	getline (cin, name);

// Determine the sex of name

	string sex; 		

	cout<<"Is "<<name<<" male, or female? \n";
	getline (cin, sex);
	
// Enforce a male or female response, or loop forever
		
	while ((strcmp (sex, "male") != 1) || (strcmp (sex, "female") != 1))
{
	cout<<"No, really.  You have to chose one of the above.  Male, or Female? \n";
	getline (cin, sex);
}

This code works if I use plain words (ex: "male", and "female", above) without using a string (ex: sex, above). Two strings or one, it fails with the following error:

loop.cpp:27: error: cannot convert 'std::string' to 'const char*' for argument '1' to 'int strcmp(const char*, const char*)'

I have tried to substitute "char*" for "string" in the relevant places in the code, using cin instead of getline, etc. I can make it compile then, but it fails to run past that point. It gives me "Bus error", and exits to prompt.

In case it matters, I'm compiling with G++ on OS X (or sometimes with G++ on my Debian Intel server via SSH, but it doesn't seem to matter which system).

I have found that I can substitute the following code, and it works, but it seems like this is just a workaround, and not the "right" way to do it? Correct me if I'm wrong...

while ((sex != "male") && (sex != "Male") && (sex != "female") && (sex != "Female"))

In other words, the program runs and behaves as expected, but since this is a learning exercise, I want to learn the correct/preferred way to do this. Thanks in advance.

[helios]

Nope. That is the right way. std::strings have the six relational operators overloaded to take as the right-hand operand both std::strings and 'char *'s.

strcmp() is only used to compare C strings to other C strings.

[grcunning]

I've been taught that the second way is actually the correct way to do it, that is to compare the strings directly, rather than having to call a function

[thejmfc]

Huh. Well, that takes care of that then.

Quick follow-up question: Can I reduce the length of that line by making it case-insensitive? I read that there was a modifier for strcmp() (strcmpi()), but that's as far as I got. In other words, is there a way to case-insensitive the thing as it is written, sans strcmp()?

EDIT: I realized that I was being lazy, and searched a bit. Seems I can write my own class of string to make it case-insensitive? Sounds like something not really worth doing unless it was a rather widespread issue in a given program. There's no simpler, built-in, way of accomplishing this?

[Zaita]

Just loop over it and call toupper() or tolower() on each element. Then you only have to do 1 compare.