6.6 接口与多态

6.6 接口与多态

由接口产生的多态指：不同的类在实现同一个接口时有可能具有不同的实现方式，那么接口变量在回调接口的时候就可能具有多种形态

//例子
public interface Example6_4_CompurerAverage {
	public double average(double d1, double d2);
}

public class Example6_4_A implements Example6_4_CompurerAverage {

	@Override
	public double average(double d1, double d2) {
		double aver = 0;
		aver = (d1 + d2)/2;
		return aver;
	}

}

public class Example6_4_B implements Example6_4_CompurerAverage {

	@Override
	public double average(double d1, double d2) {
		double aver = 0;
		aver = Math.sqrt(d1*d2);
		return aver;
	}
}

public class Example6_4 {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
Example6_4_CompurerAverage compurerAverage;
double d1=11.23;
double d2=22.78;
compurerAverage=new Example6_4_A();
double result =compurerAverage.average(d1, d2);
System.out.printf("%5.2f和%5.2f的算术平均值是：%5.2f\n",d1,d2,result);

compurerAverage=new Example6_4_B();
result =compurerAverage.average(d1, d2);
System.out.printf("%5.2f和%5.2f的几何平均值是：%5.2f",d1,d2,result);

}

}

/*输出结果：
11.23和22.78的算术平均值是：17.01
11.23和22.78的几何平均值是：15.99*/