泛型和继承演示

open abstract class ParentTest<in T> {
        abstract fun hello(other: T): Int
    }

    open abstract class MyAB<T> : ParentTest<T>() {


    }

    class MyImp1 : MyAB<Double>() {
        override fun hello(other: Double): Int {
//            TODO("not implemented") //To change body of created functions use File | Settings | File Templates.
            println("hello,you call ")
            return 1;
        }


    }


    fun demo(x: ParentTest<Double>) {
        x.hello(1.0) // 1.0 has type Double, which is a subtype of Number
        // Thus, we can assign x to a variable of type ParentTest<Double>
        val y: ParentTest<Double> = x // OK!
    }

/*
    fun demo1(x: ParentTest<Int>) {
        x.hello(1.0) // 1.0 has type Double, which is a subtype of Number
        // Thus, we can assign x to a variable of type ParentTest<Double>
        val y: ParentTest<Double> = x // OK!
    }
*/

    demo(MyImp1());
//    demo1(MyImp1());//err musct int