Java Community | Help. Code. Learn.•3y ago

Object sequential searching using compareTo()

I have this simple method to search for an object that uses

Comparable

Comparable

Comparable

Comparable interface. But I'm wondering, why does my parameter should use

extends

extends

extends

extends instead of

implements

implements

implements

implements? Doesn't this break the law where an object can only extend ONE class, but is able to implement multiple interfaces? So why doesn't

implements

implements

implements

implements work here?

    public static <T extends Comparable<T>> int sequentialSearch(T[] list, T key) {
        for (int i = 0; i < list.length; i++) {
            if (list[i].compareTo(key) == 0)
                return i;
        }
        return -1;
    }

    public static <T extends Comparable<T>> int sequentialSearch(T[] list, T key) {
        for (int i = 0; i < list.length; i++) {
            if (list[i].compareTo(key) == 0)
                return i;
        }
        return -1;
    }

    public static <T extends Comparable<T>> int sequentialSearch(T[] list, T key) {
        for (int i = 0; i < list.length; i++) {
            if (list[i].compareTo(key) == 0)
                return i;
        }
        return -1;
    }

    public static <T extends Comparable<T>> int sequentialSearch(T[] list, T key) {
        for (int i = 0; i < list.length; i++) {
            if (list[i].compareTo(key) == 0)
                return i;
        }
        return -1;
    }

JavaBot•5/25/23, 3:16 AM

JavaBot•5/25/23, 3:17 AM

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circleOP•5/25/23, 3:18 AM

why isn't it: <T Comparable<T>><T Comparable<T>>

circleOP•5/25/23, 3:37 AM

Another method I can use is using raw implementation of casting the to be compared object to

Comparable

Comparable

interface. But this still means it was casted to a class(?) instead of the interface.

    public static int sequentialSearch(Object[] x, Object key) {
        for (int i = 0; i < x.length; i++) {
            if ( ((Comparable) x[i]).compareTo(key) == 0 )
                return i;
        }
        return -1;
    }

    public static int sequentialSearch(Object[] x, Object key) {
        for (int i = 0; i < x.length; i++) {
            if ( ((Comparable) x[i]).compareTo(key) == 0 )
                return i;
        }
        return -1;
    }

JavaBot•5/25/23, 11:30 AM

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Ooppa @circle Interfaces do not implement other interfaces, they can tho be extended ...

circleOP•5/29/23, 6:50 AM

Sorry for the late reply, does that mean T as the parameter data type is already an interface?

circleOP•5/29/23, 6:52 AM

TIA

JavaBot•5/29/23, 12:10 PM

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Ooppa @circle no T may be any data type that implements the `Comparable` Interface E...

circleOP•5/31/23, 4:41 PM

So T can be extended into any interface? Even though interface is not a class?

Carter3&1/2•5/31/23, 5:05 PM

T extends InterfaceB & InterfaceCT extends InterfaceB & InterfaceC is valid syntax

JavaBot•5/31/23, 10:20 PM

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