Question

定义一个JAVA类，由构造方法初始化一个值作为一个正方形的边长， 该类计算出正方形的面积

Answer 1

public class Area {
private double l = 0.0;

public double Area(double l) {
double area = l*l;
return area;
}

public static void main(String[] args) {
Area a = new Area();
double area = 0.0;
double t = 2.0;
area = a.Area(t);
System.out.println(area);
}
}

Answer 2

package lhl;
public class java2 {
public static void main(String[] args){
int a=10;
int mj=area(a);
System.out.println("面积="+mj);
}
public static int area(int x) {
int ss=x*x;
return ss;
}
}

Answer 3

public class Zhengfangxing {
private int l;
public Zhengfangxing(int l){//有参构造函数
this.l=l;
}
public int getL() {
return l;
}
public void setL(int l) {
this.l = l;
}
public int area(){//求正方形的面积
int area=l*l;
return area;
}
public static void main(String[] args){
Zhengfangxing zfg=new Zhengfangxing(4);//创建对象
System.out.println(zfg.area());
}
}