Java 改错:根据底和高求三角形面积,

public class Square{
public static void main(String[] args){
private double a;
private double b;
Square(double a,double b){
this.a = a;
this.b = b;
}
public double getHeight(){
return a;
}
public double getBase (){
return b;
}

    public double Area(){
        double s1=(a*b)*1/2;
        return s1;
    }    
}

}
报错内容如下:
Square.java:3: 错误: 非法的表达式开始
private double a;
^
Square.java:21: 错误: 需要 class、interface、enum 或 record
}
^
2 个错误

整体的结构有些问题，以下代码你参考一下吧。

public class Square{   
    private double a;
    private double b;
    public Square(double a,double b){
        this.a = a;
        this.b = b;
    }
    public double getHeight(){
        return a;
    }
    public double getBase (){
     return b;
    }
    
    public double area(){
        double s1=(a*b)*1/2;
        return s1;    
    }
    public static void main(String[] args){
        Square square = new Square(3.0,4.0);
        double area = square.area();
        System.out.println("三角形的面积是："+area);
    }
}