string class has no overloaded "==" operator. You can do

uhmm, what about the;


how would compare to null...

btw, thank you...

Given char temp[100]; I guess you must be talking of how to determine is a string is empty. How about something like if(strlen(temp) == 0) { }.

Does it work in C++ like this?:

its not working, i just press enter but it does not alert me that i placed nothing... T_T

>i just want to know how to compare a string to null
You don't. NULL is a null pointer and a string object isn't a pointer. Most likely you want to check for an empty string:
or
And such.

>this is what my mentor told me to do...
Your mentor probably thought you were using C-style strings simulated with pointers. Your sample code isn't though, so that advice is useless.

>string class has no overloaded "==" operator.
Yes, it does. That's one of the selling points of the class.

>i just press enter but it does not alert me that i placed nothing...
Post your full program. We don't like playing 20 questions.

> i just press enter but it does not alert me that i placed nothing.

Maybe the newline is getting the best of you...

In c++ you can compare a "null string" by going (x != npos) Cant you?

There is no 'null string' as such, only null pointers. A string instance can't be null because it has just been instantiated. And x != string::npos doesn't make sense either, one is a string object while the other is most probably an unsigned integer.