面向对象练习题.doc

定义一个圆类Cirlce,能根据半径计算圆积和周长。要求类中有属性和方法。lassCircle{privateintr;finaldoublePI=;ircle(){}ircle(intr){=r;}publicdoublegetArea(){returnPI*r*r;}publicdoublegetC(){return2*PI*r;}publicstaticvoidmain(Stringargs[]){Circlec=newCircle(2);("圆的面积:"+()+"\n圆的周长:"+());}}定义一个圆柱体类,有半径、高等属性,有计算圆柱体的表面积和体积的方法。编程实现圆柱体的体积和表面积。lassCircle{privateintr;privateinth;finaldoublePI=;ircle(intr,inth){=r;=h;}ircle(){}publicdoublegetArea(){return(2*PI*r*r+2*PI*r*h);}publicdoublegetV(){returnr*PI*r*h;}publicstaticvoidmain(Stringargs[]){Circlec=newCircle(2,3);("圆柱体的面积:"+()+"\n圆柱体的体积:"+());}}编写一个计算器类,有三个属性a(int型)、b(int型)和result(double型),有计算加、减、乘、除等方法。lassji{privateinta;privateintb;privatedoubleresult=0;publicji(inta,intb){=a;=b;}publicvoidsum(){result=a+b;("运算结果为:"+result);}publicvoidsub(){result=a-b;(a+"-"+b+"运算结果为:"+result);}publicvoidchen(){result=a*b;(a+"*"+b+"运算结果为:"+result);}publicvoidchu(){result=a/b;(a+"/"+b+"运算结果为:"+result);}publicstaticvoidmain(Stringargs[]){jik=newji(4,3);();();();();}}编程计算(n个a),要求将a和n设为类的属性,可以对a和n进行初始化,编写计算求和的方法及主方法计算a=4,n=6的和。lassjisuan{privateinta;privateintn;publicjisuan(inta,intn){=a;=n;}publicintsum(){intt=0,s=0;for(inti=1;i<=n;i++){t=t*10+a;s=s+t;}returns;}publicstaticvo