阅读以下说明和Java程序,将应填入(n)处的字句写在对应栏内 [说明] 以下程序的功能时三角形、矩

阅读以下说明和Java程序，将应填入(n)处的字句写在对应栏内

[说明]

以下程序的功能时三角形、矩形和正方形的面积输出。

程序由5个类组成：areatest是主类，类Triangle，Rectangle和Square分别表示三角形、矩形和正方形，抽象类Figure提供了一个计算面积的抽象方法。

[Java程序]

public class areatest {

public static viod main(string args[]){

Figure[]Figures={

New triangle(2,3,3),new rectangle(5,8),new square(5)

};

for(int i=0; i＜Figures.length;i++){

system.out.println(Figures+"area="+Figures.getarea());

}

}

}

public abstract class figure {

public abstract double getarea();

}

public class rectangle extends (1) {

double height;

double width;

public rectangle (double height,double width){

this.height=height;

this.width=width;

}

public string tostring(){

return"rectangle:height="+height+",width="+width+":";

}

public double getarea(){

return (2)

}

}

public class square exends (3)

{

public square(double width){

(4);

}

public string tostring(){

return"square:width="+width":";

}

}

public class triangle entends (5)

{

double la;

double lb;

double lc;

public triangle(double la,double lb,double lc){

this.la=la;this.lb=lb;this.lc=lc;

}

public string tostring()(

return"triangle:sides="+la+","+lb+","+lc+":";

}

public double get area(){

double s=(la+lb+lc)/2.0;

return math．sqrt(s*(s-la)*(s-lb)*(s-lc));

}

}

正确答案：

(1) Figure (2) height*width (3) rectangle (4) super(widthwidth) (5) Figure(1) Figure (2) height*width (3) rectangle (4) super(width,width) (5) Figure 解析：本题考查Java编程。 Figure类是一个抽象类，其他三个类rectangle、square、triangle都要直接或间接继承该类，所以(1) (5)