1.說出下面程序的執(zhí)行結(jié)果:
interface?InterfaceA?{?String?S?=?"good?";?void?f();?}??abstract?class?ClassA?{?abstract?void?g();?}??class?ClassB?extends?ClassA?implements?InterfaceA?{?void?g()?{?System.out.print(S);?}??public?void?f()?{?System.out.print("?"+?S);?}?}?public?class?Test?{?public?static?void?main(String[]?args)?{?ClassA?a?=?new?ClassB();?InterfaceA?b?=?new?ClassB();?a.g();?b.f();?}?}?classB類繼承了抽象類classA并實classB類繼承了抽象類classA并實現(xiàn)了接口interfaceA，在classB中覆寫了抽象類A的g方法，還定義了接口A的方法，最終在main函數(shù)中，向上實例化一個抽象類A的實例a，一個接口A的實例b，通過a,b來調(diào)用他們各自的方法，則輸出一個good（來自a.g()）和一個（空格）good（來自b.f）。
2.編程題:
利用接口做參數(shù)，寫個計算器，能完成加減乘除運算。
（1）定義一個接口Compute含有一個方法int computer(int n,int m)。
（2）設(shè)計四個類分別實現(xiàn)此接口，完成加減乘除運算。
（3）設(shè)計一個類UseCompute，類中含有方法：public void useCom(Compute com,int one,int two)，此方法能夠用傳遞過來的對象調(diào)用computer方法完成運算，并輸出運算的結(jié)果。
（4）設(shè)計一個主類Test，調(diào)用UseCompute中的方法useCom來完成加減乘除運算。
interface?ICompute{????int?computer(int?n,int?m);}class?UseCompute{????private?int?n;????private?int?m;????public?void?useCom(ICompute?com,int?one,int?two){????????this.n=one;????????this.m=two;????????com.computer(n,m);????}}class?Add?implements?ICompute{????????private?int?n;????????private?int?m;????????private?int?result;????????public?int?computer(int?n,int?m){????????????this.m=m;????????????this.n=n;????????????this.result=n+m;????????????System.out.println("n+m?is"?+?result);????????????return?result;????????}}class?Minus?implements?ICompute{????private?int?n;????private?int?m;????private?int?result;????public?int?computer(int?n,int?m){????????this.m=m;????????this.n=n;????????this.result=n-m;????????System.out.println("n-m?is"?+result);????????return?result;????}}class?Mul?implements?ICompute{????private?int?n;????private?int?m;????private?int?result;????public?int?computer(int?n,int?m){????????this.m=m;????????this.n=n;????????this.result=n*m;????????System.out.println("n*m?is"?+result);????????return?result;????}}class?Div?implements?ICompute{????private?int?n;????private?int?m;????private?int?result;????public?int?computer(int?n,int?m){????????this.m=m;????????this.n=n;????????this.result=n/m;????????System.out.println("n/m?is"?+result);????????return?result;????}}public?class?Test?{????public?static?void?main(String[]?args)?{????????UseCompute?a=new?UseCompute();????????a.useCom(new?Add(),8,2);????????a.useCom(new?Minus(),8,2);????????a.useCom(new?Mul(),8,2);????????a.useCom(new?Div(),8,2);????}}3.按如下要求編寫Java程序：
（1）定義接口A，里面包含值為3.14的常量PI和抽象方法double area()。
（2）定義接口B，里面包含抽象方法void setColor(String c)。
（3）定義接口C，該接口繼承了接口A和B，里面包含抽象方法void volume()。
（4）定義圓柱體類Cylinder實現(xiàn)接口C，該類中包含三個成員變量：底圓半徑radius、
圓柱體的高height、顏色color。
（5）創(chuàng)建主類來測試類Cylinder。
interface?A?{????double?PI=3.14;????void?doubleArea();}interface?B{????void?setColor(String?c);}interface?C?extends?A,B?{????void?volume();}abstract?class?tmp?implements?C{????public?void?doubleArea(){};????public?void?setColor(String?c){};????public?void?volume(){};}class?Cylinder?extends?tmp{????private?double?PI=3.14;????private?double?radius;????private?double?height;????private?String?color;????public?void?doubleArea(double?radius){????????this.radius=radius;????????System.out.println("radius?is?"+(radius*PI));????}????public?void?setColor(String?c){????????this.color=c; ????????System.out.println("color?is?"+color);????}????public?void?volume(double?radius,double?height){????????this.height=height;????????this.radius=radius;????????System.out.println("volume?is?"+(radius*height*PI)); }}class?Example{????public?static?void?main(String?[]args){????????Cylinder?cyl1=new?Cylinder();????????cyl1.doubleArea(3.00);????????cyl1.setColor("原諒綠");????????cyl1.volume(3.00,3.00);????}}以上就是天津卓眾教育java培訓(xùn)機構(gòu)的小編針對“基礎(chǔ)學(xué)習(xí)教程：Java接口練習(xí)題”的內(nèi)容進行的回答，希望對大家有所幫助，如有疑問，請在線咨詢，有專業(yè)老師隨時為你服務(wù)。
