package homework;

public class Calculator {

int a;

int b;

double result;

public double sum(){

double sum=a+b;

return result=sum;

}

public double sub(){

double sub=a-b;

return result=sub;

}

public double mult(){

double mult=a*b;

return result=mult;

}

public void div(){

if(b==0){

System.out.println("b!=0");

}else{

double div=a/b;

System.out.println("result="+div);

}

}

public Calculator(int a,int b){

}

}

package homework;

public class CalculatorText {

public static void main(String[] args) {

// TODO Auto-generated method stub

Calculator Calculator1 =new Calculator(3,4);

System.out.println(Calculator1.sum());

System.out.println(Calculator1.sub());

System.out.println(Calculator1.mult());

       Calculator1.div();

Calculator Calculator2 =new Calculator(2,1);

System.out.println(Calculator2.sum());

System.out.println(Calculator2.sub());

System.out.println(Calculator2.mult());

Calculator2.div();

}

}

这是两个代码 我做了一个测试类测试。但是算出来的答案不对。