1.求矩形面积

public class juxing {

  double Chang;
    
     double Kuan;

    void M(double x1,double x2)
    {
        Chang = x1;
        
        Kuan=x2;
        
        double MianJi=Chang*Kuan;
        
        System.out.println("矩形的面积="+MianJi);
        
    }
    
    
         //属性
    double chang1=22;
    
    double kuai2=11;
    
    public double MJ(double c1,double v1)
    
    {
        double a =c1;
        
        double b =v1;
        
        return a*b;
        
}


public class ceshi {

    public static void main(String[] args) {
        
            juxing S=new juxing();
            
            S.M(23,11);
            
               System.out.println("长方形的面积是"+S.Chang*S.Kuan);

              
        
        
               //新的面积
               
               juxing dx=new juxing();
               
               dx.MJ(33, 44);
               
               System.out.println("新1的面积是="+dx.chang1*dx.kuai2);
               
               System.out.println("新2的面积是="+dx.MJ(33, 44));
        }

    }