最后要按矩形的面积从小到大排序输出它的长,宽,面积,周长。
public class rectengle {
private double length ;
private double width ;
private static int numberOfrectengles =0;
public rectengle() {
numberOfrectengles++;
}
public rectengle(double newlength,double newwidth) {
length = newlength;
width = newwidth;
numberOfrectengles++;
}
public double getlength() {
return length;
}
public void setlength(double newlength) {
length = (newlength >= 0) ? newlength : 0;
}
public double getwidth() {
return width;
}
public void setwidth(double newwidth) {
width = (newwidth >= 0) ? newwidth : 0;
}
public static int getNumberOfRectengles() {
return numberOfrectengles;
}
public double getPerimeter() {
return (length+width)/2;
}
public double getArea() {
return length*width;
}
public static void main(String[] args) {
rectengle[] rectengleArray;
rectengleArray= createRectengleArray();
printRectengleArray(rectengleArray);
}
public static rectengle[]createRectengleArray () {
rectengle[] rectengleArray = new rectengle[10];
for (int i = 0; i < rectengleArray.length; i++) {
rectengleArray[i] =
new rectengle(Math.random() * 100);
}
return rectengleArray;
}
public static void printRectengleArray(
rectengle [] rectengleArray) {
System.out.printf("%-30s%-15s\n", "length","width ","Area","perimeter");
for (int i = 0; i < rectengleArray.length; i++) {
System.out.printf("%-30f%-15f\n", rectengleArray[i].getlength(),
rectengleArray[i].getwidth(),
rectengleArray [i].getArea(),
rectengleArray[i].getPerimeter());
}
}
}
这步有什么错误呢