I was reading my C++ book for class, but it didn't tell how, or why const was used in this case:
Thanks!Code:bool String:: operator!() const { return length == 0; }
Edit: Excuse the space between ":: operator" I had to put it there or the BB thought I was trying to use a smiley. lol
'const' on a member function like that is a promise that the function will not change the object to which it belongs (that is, it makes no modifications to '*this'). The one exception is that it can modify member data declared to be 'mutable'.
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What does *this mean, I haven't seen it before?
I just looked up mutable. Basically, anti-const.
Well this is a pointer to the class (not the class itself, but each and every object of a class has a 'this' pointer). So *this is dereferencing the pointer (just as you might any other kind of pointer).Originally posted by steve_demaio
What does *this mean, I haven't seen it before?
I just looked up mutable. Basically, anti-const.
>>Edit: Excuse the space between ":: operator" I had to put it there or the BB thought I was trying to use a smiley. lol
You can disable smilies in a post by checking off the corresponding box below the edit-control you type your reply in...
Code:#include <cmath> #include <complex> bool euler_flip(bool value) { return std::pow ( std::complex<float>(std::exp(1.0)), std::complex<float>(0, 1) * std::complex<float>(std::atan(1.0) *(1 << (value + 2))) ).real() < 0; }
Ahh, thank you. That's much clearer now. Here is one scenario though.
Take this function:
*this refers to rp in this case right?Code:double Complex::realPart() const{ cout << *this << endl; return rp; }
I don't think it is possible for *this to refer to rp...I assume rp is private data:
In that case *this would refer to the myComplex object...Code:class Complex { public: //... double realPart() const; private: double rp; }; double Complex::realPart() const { cout<<*this<<endl; //operator << must be overloaded for const Complex& return rp; } int main() { Complex myComplex; double x=myComplex.realPart(); }
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