Contents
What is a good Hashcode?
hashCode values should be spread as evenly as possible over all ints. hashCode should be relatively quick to compute. hashCode must be deterministic (not random).
Why do we use GetHashCode?
This method is used to return the hash code for this instance. A hash code is a numeric value which is used to insert and identify an object in a hash-based collection. The GetHashCode method provides this hash code for algorithms that need quick checks of object equality.
Can 2 objects have same hashcode?
It is perfectly legal for two objects to have the same hashcode. If two objects are equal (using the equals() method) then they have the same hashcode. If two objects are not equal then they cannot have the same hashcode.
Can 2 unequal objects have same hashcode?
1) If two Objects are equal according to equal(), then calling the hashcode method on each of those two objects should produce same hashcode. 2) It is not required that if two objects are unequal according to the equal(), then calling the hashcode method on each of the two objects must produce distinct values.
When to generate equals and gethashcode method overrides?
When: Generate these overrides when you have a type that should be compared by one or more fields, instead of by object location in memory. If you’re implementing a value type, you should consider overriding the Equals method. You can gain increased performance over the default implementation of the Equals method on ValueType when you do so.
When to delegate to the base class gethashcode ( ) method?
For classes derived from Object, the GetHashCode method can delegate to the base class GetHashCode () implementation only if the derived class defines equality to be reference equality. The default implementation of GetHashCode () for reference types returns a hash code that is equivalent to the one returned by the GetHashCode (Object) method.
How to override gethashcode ( object ) for immutable references?
The default implementation of GetHashCode () for reference types returns a hash code that is equivalent to the one returned by the GetHashCode (Object) method. You can override GetHashCode () for immutable reference types.
What is the best way to get a hash code from the members?
I understand that my object should equal another instance of the object if it contains the same details (members). What is the best way to get a hash code from the class’s members? Let’s say you define equals so that two instances of Frob are equal if their Foo and their Bar are equal, but FooBar doesn’t matter.