Using HashSet

[Alexandru Savescu]

Hello, I want to use the latest collection classes from VC .NET so I chose hash_set. The collection is storing custom objects (not just plain ints) that have operator <. Can anyone show my how do define the hash_set and its corresponding hash_compare correctly? Thanks Best regards, Alexandru Savescu P.S. Interested in art? Visit this!

[Joaquin M Lopez Munoz]

You only have to define operator < for your class:

class MyClass
{
public:
...
bool operator<(const MyClass& x)const
{
// compare this and x
}
};

Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

[Alexandru Savescu]

I wish it were that easy.... I get C2440 error (cannot convert from const MyClass to size_t). I think I must derive from hash_compare and implement custom hash method as the compiler does not know how to get a hash code for my objects... Best regards, Alexandru Savescu P.S. Interested in art? Visit this!

[Joaquin M Lopez Munoz]

This sounds strange. Could you post the code to see how you're using hash_set? I think it should work once you defined operator <. Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

[Alexandru Savescu]

Here's the code: #include #include using namespace std; class MyClass { public: int x; MyClass (int a) : x (a) { } bool operator < (const MyClass& OB) const { return x < OB.x; } }; int main () { hash_set MySet; MySet.insert (MyClass (2)); } Best regards, Alexandru Savescu P.S. Interested in art? Visit this!