Questions tagged [comparable]

In Java, this interface is implemented by a class to indicate that it can be compared to another object and therefore ordered. The interface defines one method: compareTo(). Classes can either implement it as a raw type, as with older versions of Java:

public class MyClass implements Comparable
{
    public int compareTo(Object other)
    {
        MyClass toCompare = (MyClass) other;
        //...
    }
}

Or, as of Java 1.5, a class can use generics:

public class MyClass implements Comparable<MyClass>
{
    public int compareTo(MyClass other)
    {
        //...
    }
}

The general contract of compareTo() is:

• If this is less than the parameter, it returns a value less than zero.
• If this is greater than the parameter, it returns a value greater than zero.
• Otherwise, if this is equal to the parameter, returns zero.

The actual value of compareTo() is irrelevant; only the sign of the return value matters.

Javadoc for java.lang.Comparable

In Go, comparable is a predeclared interface constraint. It can be used directly or it can be embedded in other interface constraints. It cannot be used in union terms. Specifications: Type Constraints:

The predeclared interface type comparable denotes the set of all concrete (non-interface) types that are comparable. Specifically, a type T implements comparable if:

• T is not an interface type and T supports the operations == and !=; or
• T is an interface type and each type in T's type set implements comparable.

Example usage:

func IsZero[T comparable](v T) bool {
    return v == *new(T)
}