43.interface Shape double area(); double girth(); } class Rectangle implements Shape int a,b; public Rectangle(int aa,int bb)(a=aa;b=bb;} public double area()(return a b;} public double girth()(return 2*(a+b);) } public class XXK3 public static void main(String[]args){ Shape x; x=new Rectangle(6,10); System.out.println(x.area()+","+x.girth()); } 44.public class XXK4 public static void main(String[]args){ int[]a={2,5,8,10,15,20}; int s=0; for(int i=0;i<a.length;i++)s+=ai]; System.out.println("s="+s); 45.class ABC String name; double price; public ABC(String na,double pr)(name=na;price=pr;} 157943. interface Shape { double areaO ; double girthO ; class Rectangle implements Shape { int a ,b; public RectangleCint aa , int bb) {a=aa; b=bb;} public double areaO {return 铃b;} public double girthO {return 祷(a+b);} public class XXK3 { public static void main(String[] args) { Shape x; x=new Rectangle(6 ,10); System. out. println(x. areaO + ", II +x. girthO); 44. public class XXK4 { public static void main(String[] args) { int []a={2 ,5 ,8 ,10 ,15 ,20}; int s=O; for(int i=O; i<a.length; 十+)s十=a[i]; System. out. println( 十s) ; 45. class ABC { String name; double price; public ABC(String na , double pr) {name=na; price=pr;} 1579