寫了一個有參無返回值的方法代碼，求大神寫一個有參有返回值的代碼（目前什么情況下用有參有返回值的方法，什么情況下用無參無返回值的方法還不是太清楚）
package?shape;
public??abstract?class?Shape?{
//?double?i?=?0;
//?double?j?=?0;
?//public?abstract?double?perimeter(double?length,double?wide);
?public?abstract?void?perimeter(double?length,double?wide);
?public?abstract?void?perimeter(double?radious);
?public?abstract?void?area(double?length,double?wide);
?public?abstract?void?area(double?radius);
}
package?shape;
public?class?Rectangle?extends?Shape{
?public?void?perimeter(double?length,?double?wide)?{
??//?TODO?Auto-generated?method?stub
??double?perimeter?=(length?+?wide)*2;
??//return?0;
??System.out.println("矩形的周長為："?+?perimeter);
?}
?public?void?area(double?length,double?wide)?{
??//?TODO?Auto-generated?method?stub
??double?area?=?length*wide;
??System.out.println("矩形的面積為："?+?area);
??//return?area;
?}
?public?void?perimeter(double?radious)?{
??//?TODO?Auto-generated?method?stub
??//return?0;
?}
?public?void?area(double?radius)?{
??//?TODO?Auto-generated?method?stub
??//return?0;
?}
?
}

package?shape;
public?class?Circle?extends?Shape{
?public?void?perimeter(double?length,?double?wide)?{
??//?TODO?Auto-generated?method?stub
//??return?0;
?}
?public?void?perimeter(double?radious)?{
??//?TODO?Auto-generated?method?stub
??double?perimeter?=?2*Math.PI*radious;
??System.out.println("園的周長為："?+?perimeter);
//??return?perimeter;
?}
?public?void?area(double?length,?double?wide)?{
??//?TODO?Auto-generated?method?stub
//??return?0;
?}
?public?void?area(double?radius)?{
??//?TODO?Auto-generated?method?stub
??double?area?=?Math.PI*Math.pow(radius,?2);
??System.out.println("圓的的面積為："?+?area);
//??return?area;
?}
}

package?shape;
public?class?Test?{
?public?static?void?main(String[]?args)?{
??//?TODO?Auto-generated?method?stub
??Shape?sh?=?new?Rectangle();
??sh.perimeter(5,?4);
??sh.area(5,?4);
??Shape?sh1?=?new?Circle();
??sh1.perimeter(5);
??sh1.area(5);
?}
}