我写了一个计算器的类:和一个接口:
public class Calculator {public double number_A=0;public double number_B=0;public void setNumberA(double numberA){this.number_A=numberA;}public double getNumberA(){return number_A;}public void setNumberB(double numberB){this.number_B=numberB;}public double getNumberB(){return number_B;}}
public interface ICalculator {public double getResult();}然后写了4个运算类:
public class Addition extends Calculator implements ICalculator{public double getResult(){double result=0;result=number_A+number_B;return result;}}为什么到除法类的时候会报错,不解?
public class Division extends Calculator implements ICalculator {public double getResult(){double result=0;result=number_A/number_B;return result;}}number_A number_B一直是红线,不解??
public class Calculator {public double number_A=0;public double number_B=0;public void setNumberA(double numberA){this.number_A=numberA;}public double getNumberA(){return number_A;}public void setNumberB(double numberB){this.number_B=numberB;}public double getNumberB(){return number_B;}}
public interface ICalculator {public double getResult();}然后写了4个运算类:
public class Addition extends Calculator implements ICalculator{public double getResult(){double result=0;result=number_A+number_B;return result;}}为什么到除法类的时候会报错,不解?
public class Division extends Calculator implements ICalculator {public double getResult(){double result=0;result=number_A/number_B;return result;}}number_A number_B一直是红线,不解??
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不知怎样写。
import java.util.Scanner;
public class TestCalculator { /**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
Calculator cal = null;
ICalculator calc = null;
Scanner rd=new Scanner(System.in);
System.out.println("Please enter the first number:");
cal.setNumberA(rd.nextDouble());
System.out.println("Please enter the second number:");
cal.setNumberB(rd.nextDouble());
System.out.println("Please select the operator symbol:");
System.out.println("1.+ 2.- 3.* 4./");
int sign=rd.nextInt();
switch(sign)
{
case 1:
cal=new Addition();
break;
case 2:
cal=new Subtraction();
break;
case 3:
cal=new Multiplication();
break;
}
System.out.println(cal.number_A+""+sign+""+cal.number_B+"="+calc.getResult());
}